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1/* i2c-core.c - a device driver for the iic-bus interface */
2/* ------------------------------------------------------------------------- */
3/* Copyright (C) 1995-99 Simon G. Vogl
4
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details. */
14/* ------------------------------------------------------------------------- */
15
16/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
17 All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
18 SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
19 Jean Delvare <jdelvare@suse.de>
20 Mux support by Rodolfo Giometti <giometti@enneenne.com> and
21 Michael Lawnick <michael.lawnick.ext@nsn.com>
22 OF support is copyright (c) 2008 Jochen Friedrich <jochen@scram.de>
23 (based on a previous patch from Jon Smirl <jonsmirl@gmail.com>) and
24 (c) 2013 Wolfram Sang <wsa@the-dreams.de>
25 I2C ACPI code Copyright (C) 2014 Intel Corp
26 Author: Lan Tianyu <tianyu.lan@intel.com>
27 I2C slave support (c) 2014 by Wolfram Sang <wsa@sang-engineering.com>
28 */
29
30#include <dt-bindings/i2c/i2c.h>
31#include <asm/uaccess.h>
32#include <linux/acpi.h>
33#include <linux/clk/clk-conf.h>
34#include <linux/completion.h>
35#include <linux/delay.h>
36#include <linux/err.h>
37#include <linux/errno.h>
38#include <linux/gpio.h>
39#include <linux/hardirq.h>
40#include <linux/i2c.h>
41#include <linux/idr.h>
42#include <linux/init.h>
43#include <linux/irqflags.h>
44#include <linux/jump_label.h>
45#include <linux/kernel.h>
46#include <linux/module.h>
47#include <linux/mutex.h>
48#include <linux/of_device.h>
49#include <linux/of.h>
50#include <linux/of_irq.h>
51#include <linux/pm_domain.h>
52#include <linux/pm_runtime.h>
53#include <linux/pm_wakeirq.h>
54#include <linux/property.h>
55#include <linux/rwsem.h>
56#include <linux/slab.h>
57
58#include "i2c-core.h"
59
60#define CREATE_TRACE_POINTS
61#include <trace/events/i2c.h>
62
63#define I2C_ADDR_OFFSET_TEN_BIT 0xa000
64#define I2C_ADDR_OFFSET_SLAVE 0x1000
65
66/* core_lock protects i2c_adapter_idr, and guarantees
67 that device detection, deletion of detected devices, and attach_adapter
68 calls are serialized */
69static DEFINE_MUTEX(core_lock);
70static DEFINE_IDR(i2c_adapter_idr);
71
72static struct device_type i2c_client_type;
73static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
74
75static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
76static bool is_registered;
77
78void i2c_transfer_trace_reg(void)
79{
80 static_key_slow_inc(&i2c_trace_msg);
81}
82
83void i2c_transfer_trace_unreg(void)
84{
85 static_key_slow_dec(&i2c_trace_msg);
86}
87
88#if defined(CONFIG_ACPI)
89struct acpi_i2c_handler_data {
90 struct acpi_connection_info info;
91 struct i2c_adapter *adapter;
92};
93
94struct gsb_buffer {
95 u8 status;
96 u8 len;
97 union {
98 u16 wdata;
99 u8 bdata;
100 u8 data[0];
101 };
102} __packed;
103
104struct acpi_i2c_lookup {
105 struct i2c_board_info *info;
106 acpi_handle adapter_handle;
107 acpi_handle device_handle;
108};
109
110static int acpi_i2c_find_address(struct acpi_resource *ares, void *data)
111{
112 struct acpi_i2c_lookup *lookup = data;
113 struct i2c_board_info *info = lookup->info;
114 struct acpi_resource_i2c_serialbus *sb;
115 acpi_handle adapter_handle;
116 acpi_status status;
117
118 if (info->addr || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS)
119 return 1;
120
121 sb = &ares->data.i2c_serial_bus;
122 if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C)
123 return 1;
124
125 /*
126 * Extract the ResourceSource and make sure that the handle matches
127 * with the I2C adapter handle.
128 */
129 status = acpi_get_handle(lookup->device_handle,
130 sb->resource_source.string_ptr,
131 &adapter_handle);
132 if (ACPI_SUCCESS(status) && adapter_handle == lookup->adapter_handle) {
133 info->addr = sb->slave_address;
134 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
135 info->flags |= I2C_CLIENT_TEN;
136 }
137
138 return 1;
139}
140
141static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
142 void *data, void **return_value)
143{
144 struct i2c_adapter *adapter = data;
145 struct list_head resource_list;
146 struct acpi_i2c_lookup lookup;
147 struct resource_entry *entry;
148 struct i2c_board_info info;
149 struct acpi_device *adev;
150 int ret;
151
152 if (acpi_bus_get_device(handle, &adev))
153 return AE_OK;
154 if (acpi_bus_get_status(adev) || !adev->status.present)
155 return AE_OK;
156
157 memset(&info, 0, sizeof(info));
158 info.fwnode = acpi_fwnode_handle(adev);
159
160 memset(&lookup, 0, sizeof(lookup));
161 lookup.adapter_handle = ACPI_HANDLE(&adapter->dev);
162 lookup.device_handle = handle;
163 lookup.info = &info;
164
165 /*
166 * Look up for I2cSerialBus resource with ResourceSource that
167 * matches with this adapter.
168 */
169 INIT_LIST_HEAD(&resource_list);
170 ret = acpi_dev_get_resources(adev, &resource_list,
171 acpi_i2c_find_address, &lookup);
172 acpi_dev_free_resource_list(&resource_list);
173
174 if (ret < 0 || !info.addr)
175 return AE_OK;
176
177 /* Then fill IRQ number if any */
178 ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
179 if (ret < 0)
180 return AE_OK;
181
182 resource_list_for_each_entry(entry, &resource_list) {
183 if (resource_type(entry->res) == IORESOURCE_IRQ) {
184 info.irq = entry->res->start;
185 break;
186 }
187 }
188
189 acpi_dev_free_resource_list(&resource_list);
190
191 adev->power.flags.ignore_parent = true;
192 strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
193 if (!i2c_new_device(adapter, &info)) {
194 adev->power.flags.ignore_parent = false;
195 dev_err(&adapter->dev,
196 "failed to add I2C device %s from ACPI\n",
197 dev_name(&adev->dev));
198 }
199
200 return AE_OK;
201}
202
203#define ACPI_I2C_MAX_SCAN_DEPTH 32
204
205/**
206 * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
207 * @adap: pointer to adapter
208 *
209 * Enumerate all I2C slave devices behind this adapter by walking the ACPI
210 * namespace. When a device is found it will be added to the Linux device
211 * model and bound to the corresponding ACPI handle.
212 */
213static void acpi_i2c_register_devices(struct i2c_adapter *adap)
214{
215 acpi_status status;
216
217 if (!has_acpi_companion(&adap->dev))
218 return;
219
220 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
221 ACPI_I2C_MAX_SCAN_DEPTH,
222 acpi_i2c_add_device, NULL,
223 adap, NULL);
224 if (ACPI_FAILURE(status))
225 dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
226}
227
228#else /* CONFIG_ACPI */
229static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) { }
230#endif /* CONFIG_ACPI */
231
232#ifdef CONFIG_ACPI_I2C_OPREGION
233static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
234 u8 cmd, u8 *data, u8 data_len)
235{
236
237 struct i2c_msg msgs[2];
238 int ret;
239 u8 *buffer;
240
241 buffer = kzalloc(data_len, GFP_KERNEL);
242 if (!buffer)
243 return AE_NO_MEMORY;
244
245 msgs[0].addr = client->addr;
246 msgs[0].flags = client->flags;
247 msgs[0].len = 1;
248 msgs[0].buf = &cmd;
249
250 msgs[1].addr = client->addr;
251 msgs[1].flags = client->flags | I2C_M_RD;
252 msgs[1].len = data_len;
253 msgs[1].buf = buffer;
254
255 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
256 if (ret < 0)
257 dev_err(&client->adapter->dev, "i2c read failed\n");
258 else
259 memcpy(data, buffer, data_len);
260
261 kfree(buffer);
262 return ret;
263}
264
265static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
266 u8 cmd, u8 *data, u8 data_len)
267{
268
269 struct i2c_msg msgs[1];
270 u8 *buffer;
271 int ret = AE_OK;
272
273 buffer = kzalloc(data_len + 1, GFP_KERNEL);
274 if (!buffer)
275 return AE_NO_MEMORY;
276
277 buffer[0] = cmd;
278 memcpy(buffer + 1, data, data_len);
279
280 msgs[0].addr = client->addr;
281 msgs[0].flags = client->flags;
282 msgs[0].len = data_len + 1;
283 msgs[0].buf = buffer;
284
285 ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
286 if (ret < 0)
287 dev_err(&client->adapter->dev, "i2c write failed\n");
288
289 kfree(buffer);
290 return ret;
291}
292
293static acpi_status
294acpi_i2c_space_handler(u32 function, acpi_physical_address command,
295 u32 bits, u64 *value64,
296 void *handler_context, void *region_context)
297{
298 struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
299 struct acpi_i2c_handler_data *data = handler_context;
300 struct acpi_connection_info *info = &data->info;
301 struct acpi_resource_i2c_serialbus *sb;
302 struct i2c_adapter *adapter = data->adapter;
303 struct i2c_client *client;
304 struct acpi_resource *ares;
305 u32 accessor_type = function >> 16;
306 u8 action = function & ACPI_IO_MASK;
307 acpi_status ret;
308 int status;
309
310 ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
311 if (ACPI_FAILURE(ret))
312 return ret;
313
314 client = kzalloc(sizeof(*client), GFP_KERNEL);
315 if (!client) {
316 ret = AE_NO_MEMORY;
317 goto err;
318 }
319
320 if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) {
321 ret = AE_BAD_PARAMETER;
322 goto err;
323 }
324
325 sb = &ares->data.i2c_serial_bus;
326 if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) {
327 ret = AE_BAD_PARAMETER;
328 goto err;
329 }
330
331 client->adapter = adapter;
332 client->addr = sb->slave_address;
333
334 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
335 client->flags |= I2C_CLIENT_TEN;
336
337 switch (accessor_type) {
338 case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
339 if (action == ACPI_READ) {
340 status = i2c_smbus_read_byte(client);
341 if (status >= 0) {
342 gsb->bdata = status;
343 status = 0;
344 }
345 } else {
346 status = i2c_smbus_write_byte(client, gsb->bdata);
347 }
348 break;
349
350 case ACPI_GSB_ACCESS_ATTRIB_BYTE:
351 if (action == ACPI_READ) {
352 status = i2c_smbus_read_byte_data(client, command);
353 if (status >= 0) {
354 gsb->bdata = status;
355 status = 0;
356 }
357 } else {
358 status = i2c_smbus_write_byte_data(client, command,
359 gsb->bdata);
360 }
361 break;
362
363 case ACPI_GSB_ACCESS_ATTRIB_WORD:
364 if (action == ACPI_READ) {
365 status = i2c_smbus_read_word_data(client, command);
366 if (status >= 0) {
367 gsb->wdata = status;
368 status = 0;
369 }
370 } else {
371 status = i2c_smbus_write_word_data(client, command,
372 gsb->wdata);
373 }
374 break;
375
376 case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
377 if (action == ACPI_READ) {
378 status = i2c_smbus_read_block_data(client, command,
379 gsb->data);
380 if (status >= 0) {
381 gsb->len = status;
382 status = 0;
383 }
384 } else {
385 status = i2c_smbus_write_block_data(client, command,
386 gsb->len, gsb->data);
387 }
388 break;
389
390 case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
391 if (action == ACPI_READ) {
392 status = acpi_gsb_i2c_read_bytes(client, command,
393 gsb->data, info->access_length);
394 if (status > 0)
395 status = 0;
396 } else {
397 status = acpi_gsb_i2c_write_bytes(client, command,
398 gsb->data, info->access_length);
399 }
400 break;
401
402 default:
403 pr_info("protocol(0x%02x) is not supported.\n", accessor_type);
404 ret = AE_BAD_PARAMETER;
405 goto err;
406 }
407
408 gsb->status = status;
409
410 err:
411 kfree(client);
412 ACPI_FREE(ares);
413 return ret;
414}
415
416
417static int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)
418{
419 acpi_handle handle;
420 struct acpi_i2c_handler_data *data;
421 acpi_status status;
422
423 if (!adapter->dev.parent)
424 return -ENODEV;
425
426 handle = ACPI_HANDLE(adapter->dev.parent);
427
428 if (!handle)
429 return -ENODEV;
430
431 data = kzalloc(sizeof(struct acpi_i2c_handler_data),
432 GFP_KERNEL);
433 if (!data)
434 return -ENOMEM;
435
436 data->adapter = adapter;
437 status = acpi_bus_attach_private_data(handle, (void *)data);
438 if (ACPI_FAILURE(status)) {
439 kfree(data);
440 return -ENOMEM;
441 }
442
443 status = acpi_install_address_space_handler(handle,
444 ACPI_ADR_SPACE_GSBUS,
445 &acpi_i2c_space_handler,
446 NULL,
447 data);
448 if (ACPI_FAILURE(status)) {
449 dev_err(&adapter->dev, "Error installing i2c space handler\n");
450 acpi_bus_detach_private_data(handle);
451 kfree(data);
452 return -ENOMEM;
453 }
454
455 acpi_walk_dep_device_list(handle);
456 return 0;
457}
458
459static void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter)
460{
461 acpi_handle handle;
462 struct acpi_i2c_handler_data *data;
463 acpi_status status;
464
465 if (!adapter->dev.parent)
466 return;
467
468 handle = ACPI_HANDLE(adapter->dev.parent);
469
470 if (!handle)
471 return;
472
473 acpi_remove_address_space_handler(handle,
474 ACPI_ADR_SPACE_GSBUS,
475 &acpi_i2c_space_handler);
476
477 status = acpi_bus_get_private_data(handle, (void **)&data);
478 if (ACPI_SUCCESS(status))
479 kfree(data);
480
481 acpi_bus_detach_private_data(handle);
482}
483#else /* CONFIG_ACPI_I2C_OPREGION */
484static inline void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter)
485{ }
486
487static inline int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)
488{ return 0; }
489#endif /* CONFIG_ACPI_I2C_OPREGION */
490
491/* ------------------------------------------------------------------------- */
492
493static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
494 const struct i2c_client *client)
495{
496 while (id->name[0]) {
497 if (strcmp(client->name, id->name) == 0)
498 return id;
499 id++;
500 }
501 return NULL;
502}
503
504static int i2c_device_match(struct device *dev, struct device_driver *drv)
505{
506 struct i2c_client *client = i2c_verify_client(dev);
507 struct i2c_driver *driver;
508
509 if (!client)
510 return 0;
511
512 /* Attempt an OF style match */
513 if (of_driver_match_device(dev, drv))
514 return 1;
515
516 /* Then ACPI style match */
517 if (acpi_driver_match_device(dev, drv))
518 return 1;
519
520 driver = to_i2c_driver(drv);
521 /* match on an id table if there is one */
522 if (driver->id_table)
523 return i2c_match_id(driver->id_table, client) != NULL;
524
525 return 0;
526}
527
528static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
529{
530 struct i2c_client *client = to_i2c_client(dev);
531 int rc;
532
533 rc = acpi_device_uevent_modalias(dev, env);
534 if (rc != -ENODEV)
535 return rc;
536
537 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
538}
539
540/* i2c bus recovery routines */
541static int get_scl_gpio_value(struct i2c_adapter *adap)
542{
543 return gpio_get_value(adap->bus_recovery_info->scl_gpio);
544}
545
546static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
547{
548 gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
549}
550
551static int get_sda_gpio_value(struct i2c_adapter *adap)
552{
553 return gpio_get_value(adap->bus_recovery_info->sda_gpio);
554}
555
556static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
557{
558 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
559 struct device *dev = &adap->dev;
560 int ret = 0;
561
562 ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN |
563 GPIOF_OUT_INIT_HIGH, "i2c-scl");
564 if (ret) {
565 dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio);
566 return ret;
567 }
568
569 if (bri->get_sda) {
570 if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) {
571 /* work without SDA polling */
572 dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n",
573 bri->sda_gpio);
574 bri->get_sda = NULL;
575 }
576 }
577
578 return ret;
579}
580
581static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
582{
583 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
584
585 if (bri->get_sda)
586 gpio_free(bri->sda_gpio);
587
588 gpio_free(bri->scl_gpio);
589}
590
591/*
592 * We are generating clock pulses. ndelay() determines durating of clk pulses.
593 * We will generate clock with rate 100 KHz and so duration of both clock levels
594 * is: delay in ns = (10^6 / 100) / 2
595 */
596#define RECOVERY_NDELAY 5000
597#define RECOVERY_CLK_CNT 9
598
599static int i2c_generic_recovery(struct i2c_adapter *adap)
600{
601 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
602 int i = 0, val = 1, ret = 0;
603
604 if (bri->prepare_recovery)
605 bri->prepare_recovery(adap);
606
607 bri->set_scl(adap, val);
608 ndelay(RECOVERY_NDELAY);
609
610 /*
611 * By this time SCL is high, as we need to give 9 falling-rising edges
612 */
613 while (i++ < RECOVERY_CLK_CNT * 2) {
614 if (val) {
615 /* Break if SDA is high */
616 if (bri->get_sda && bri->get_sda(adap))
617 break;
618 /* SCL shouldn't be low here */
619 if (!bri->get_scl(adap)) {
620 dev_err(&adap->dev,
621 "SCL is stuck low, exit recovery\n");
622 ret = -EBUSY;
623 break;
624 }
625 }
626
627 val = !val;
628 bri->set_scl(adap, val);
629 ndelay(RECOVERY_NDELAY);
630 }
631
632 if (bri->unprepare_recovery)
633 bri->unprepare_recovery(adap);
634
635 return ret;
636}
637
638int i2c_generic_scl_recovery(struct i2c_adapter *adap)
639{
640 return i2c_generic_recovery(adap);
641}
642EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
643
644int i2c_generic_gpio_recovery(struct i2c_adapter *adap)
645{
646 int ret;
647
648 ret = i2c_get_gpios_for_recovery(adap);
649 if (ret)
650 return ret;
651
652 ret = i2c_generic_recovery(adap);
653 i2c_put_gpios_for_recovery(adap);
654
655 return ret;
656}
657EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery);
658
659int i2c_recover_bus(struct i2c_adapter *adap)
660{
661 if (!adap->bus_recovery_info)
662 return -EOPNOTSUPP;
663
664 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
665 return adap->bus_recovery_info->recover_bus(adap);
666}
667EXPORT_SYMBOL_GPL(i2c_recover_bus);
668
669static int i2c_device_probe(struct device *dev)
670{
671 struct i2c_client *client = i2c_verify_client(dev);
672 struct i2c_driver *driver;
673 int status;
674
675 if (!client)
676 return 0;
677
678 if (!client->irq) {
679 int irq = -ENOENT;
680
681 if (dev->of_node) {
682 irq = of_irq_get_byname(dev->of_node, "irq");
683 if (irq == -EINVAL || irq == -ENODATA)
684 irq = of_irq_get(dev->of_node, 0);
685 } else if (ACPI_COMPANION(dev)) {
686 irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
687 }
688 if (irq == -EPROBE_DEFER)
689 return irq;
690 if (irq < 0)
691 irq = 0;
692
693 client->irq = irq;
694 }
695
696 driver = to_i2c_driver(dev->driver);
697 if (!driver->probe || !driver->id_table)
698 return -ENODEV;
699
700 if (client->flags & I2C_CLIENT_WAKE) {
701 int wakeirq = -ENOENT;
702
703 if (dev->of_node) {
704 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
705 if (wakeirq == -EPROBE_DEFER)
706 return wakeirq;
707 }
708
709 device_init_wakeup(&client->dev, true);
710
711 if (wakeirq > 0 && wakeirq != client->irq)
712 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
713 else if (client->irq > 0)
714 status = dev_pm_set_wake_irq(dev, client->irq);
715 else
716 status = 0;
717
718 if (status)
719 dev_warn(&client->dev, "failed to set up wakeup irq");
720 }
721
722 dev_dbg(dev, "probe\n");
723
724 status = of_clk_set_defaults(dev->of_node, false);
725 if (status < 0)
726 goto err_clear_wakeup_irq;
727
728 status = dev_pm_domain_attach(&client->dev, true);
729 if (status == -EPROBE_DEFER)
730 goto err_clear_wakeup_irq;
731
732 status = driver->probe(client, i2c_match_id(driver->id_table, client));
733 if (status)
734 goto err_detach_pm_domain;
735
736 return 0;
737
738err_detach_pm_domain:
739 dev_pm_domain_detach(&client->dev, true);
740err_clear_wakeup_irq:
741 dev_pm_clear_wake_irq(&client->dev);
742 device_init_wakeup(&client->dev, false);
743 return status;
744}
745
746static int i2c_device_remove(struct device *dev)
747{
748 struct i2c_client *client = i2c_verify_client(dev);
749 struct i2c_driver *driver;
750 int status = 0;
751
752 if (!client || !dev->driver)
753 return 0;
754
755 driver = to_i2c_driver(dev->driver);
756 if (driver->remove) {
757 dev_dbg(dev, "remove\n");
758 status = driver->remove(client);
759 }
760
761 dev_pm_domain_detach(&client->dev, true);
762
763 dev_pm_clear_wake_irq(&client->dev);
764 device_init_wakeup(&client->dev, false);
765
766 return status;
767}
768
769static void i2c_device_shutdown(struct device *dev)
770{
771 struct i2c_client *client = i2c_verify_client(dev);
772 struct i2c_driver *driver;
773
774 if (!client || !dev->driver)
775 return;
776 driver = to_i2c_driver(dev->driver);
777 if (driver->shutdown)
778 driver->shutdown(client);
779}
780
781static void i2c_client_dev_release(struct device *dev)
782{
783 kfree(to_i2c_client(dev));
784}
785
786static ssize_t
787show_name(struct device *dev, struct device_attribute *attr, char *buf)
788{
789 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
790 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
791}
792static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
793
794static ssize_t
795show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
796{
797 struct i2c_client *client = to_i2c_client(dev);
798 int len;
799
800 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
801 if (len != -ENODEV)
802 return len;
803
804 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
805}
806static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
807
808static struct attribute *i2c_dev_attrs[] = {
809 &dev_attr_name.attr,
810 /* modalias helps coldplug: modprobe $(cat .../modalias) */
811 &dev_attr_modalias.attr,
812 NULL
813};
814ATTRIBUTE_GROUPS(i2c_dev);
815
816struct bus_type i2c_bus_type = {
817 .name = "i2c",
818 .match = i2c_device_match,
819 .probe = i2c_device_probe,
820 .remove = i2c_device_remove,
821 .shutdown = i2c_device_shutdown,
822};
823EXPORT_SYMBOL_GPL(i2c_bus_type);
824
825static struct device_type i2c_client_type = {
826 .groups = i2c_dev_groups,
827 .uevent = i2c_device_uevent,
828 .release = i2c_client_dev_release,
829};
830
831
832/**
833 * i2c_verify_client - return parameter as i2c_client, or NULL
834 * @dev: device, probably from some driver model iterator
835 *
836 * When traversing the driver model tree, perhaps using driver model
837 * iterators like @device_for_each_child(), you can't assume very much
838 * about the nodes you find. Use this function to avoid oopses caused
839 * by wrongly treating some non-I2C device as an i2c_client.
840 */
841struct i2c_client *i2c_verify_client(struct device *dev)
842{
843 return (dev->type == &i2c_client_type)
844 ? to_i2c_client(dev)
845 : NULL;
846}
847EXPORT_SYMBOL(i2c_verify_client);
848
849
850/* Return a unique address which takes the flags of the client into account */
851static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
852{
853 unsigned short addr = client->addr;
854
855 /* For some client flags, add an arbitrary offset to avoid collisions */
856 if (client->flags & I2C_CLIENT_TEN)
857 addr |= I2C_ADDR_OFFSET_TEN_BIT;
858
859 if (client->flags & I2C_CLIENT_SLAVE)
860 addr |= I2C_ADDR_OFFSET_SLAVE;
861
862 return addr;
863}
864
865/* This is a permissive address validity check, I2C address map constraints
866 * are purposely not enforced, except for the general call address. */
867static int i2c_check_addr_validity(unsigned addr, unsigned short flags)
868{
869 if (flags & I2C_CLIENT_TEN) {
870 /* 10-bit address, all values are valid */
871 if (addr > 0x3ff)
872 return -EINVAL;
873 } else {
874 /* 7-bit address, reject the general call address */
875 if (addr == 0x00 || addr > 0x7f)
876 return -EINVAL;
877 }
878 return 0;
879}
880
881/* And this is a strict address validity check, used when probing. If a
882 * device uses a reserved address, then it shouldn't be probed. 7-bit
883 * addressing is assumed, 10-bit address devices are rare and should be
884 * explicitly enumerated. */
885static int i2c_check_7bit_addr_validity_strict(unsigned short addr)
886{
887 /*
888 * Reserved addresses per I2C specification:
889 * 0x00 General call address / START byte
890 * 0x01 CBUS address
891 * 0x02 Reserved for different bus format
892 * 0x03 Reserved for future purposes
893 * 0x04-0x07 Hs-mode master code
894 * 0x78-0x7b 10-bit slave addressing
895 * 0x7c-0x7f Reserved for future purposes
896 */
897 if (addr < 0x08 || addr > 0x77)
898 return -EINVAL;
899 return 0;
900}
901
902static int __i2c_check_addr_busy(struct device *dev, void *addrp)
903{
904 struct i2c_client *client = i2c_verify_client(dev);
905 int addr = *(int *)addrp;
906
907 if (client && i2c_encode_flags_to_addr(client) == addr)
908 return -EBUSY;
909 return 0;
910}
911
912/* walk up mux tree */
913static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
914{
915 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
916 int result;
917
918 result = device_for_each_child(&adapter->dev, &addr,
919 __i2c_check_addr_busy);
920
921 if (!result && parent)
922 result = i2c_check_mux_parents(parent, addr);
923
924 return result;
925}
926
927/* recurse down mux tree */
928static int i2c_check_mux_children(struct device *dev, void *addrp)
929{
930 int result;
931
932 if (dev->type == &i2c_adapter_type)
933 result = device_for_each_child(dev, addrp,
934 i2c_check_mux_children);
935 else
936 result = __i2c_check_addr_busy(dev, addrp);
937
938 return result;
939}
940
941static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
942{
943 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
944 int result = 0;
945
946 if (parent)
947 result = i2c_check_mux_parents(parent, addr);
948
949 if (!result)
950 result = device_for_each_child(&adapter->dev, &addr,
951 i2c_check_mux_children);
952
953 return result;
954}
955
956/**
957 * i2c_lock_adapter - Get exclusive access to an I2C bus segment
958 * @adapter: Target I2C bus segment
959 */
960void i2c_lock_adapter(struct i2c_adapter *adapter)
961{
962 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
963
964 if (parent)
965 i2c_lock_adapter(parent);
966 else
967 rt_mutex_lock(&adapter->bus_lock);
968}
969EXPORT_SYMBOL_GPL(i2c_lock_adapter);
970
971/**
972 * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
973 * @adapter: Target I2C bus segment
974 */
975static int i2c_trylock_adapter(struct i2c_adapter *adapter)
976{
977 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
978
979 if (parent)
980 return i2c_trylock_adapter(parent);
981 else
982 return rt_mutex_trylock(&adapter->bus_lock);
983}
984
985/**
986 * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
987 * @adapter: Target I2C bus segment
988 */
989void i2c_unlock_adapter(struct i2c_adapter *adapter)
990{
991 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
992
993 if (parent)
994 i2c_unlock_adapter(parent);
995 else
996 rt_mutex_unlock(&adapter->bus_lock);
997}
998EXPORT_SYMBOL_GPL(i2c_unlock_adapter);
999
1000static void i2c_dev_set_name(struct i2c_adapter *adap,
1001 struct i2c_client *client)
1002{
1003 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
1004
1005 if (adev) {
1006 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
1007 return;
1008 }
1009
1010 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
1011 i2c_encode_flags_to_addr(client));
1012}
1013
1014/**
1015 * i2c_new_device - instantiate an i2c device
1016 * @adap: the adapter managing the device
1017 * @info: describes one I2C device; bus_num is ignored
1018 * Context: can sleep
1019 *
1020 * Create an i2c device. Binding is handled through driver model
1021 * probe()/remove() methods. A driver may be bound to this device when we
1022 * return from this function, or any later moment (e.g. maybe hotplugging will
1023 * load the driver module). This call is not appropriate for use by mainboard
1024 * initialization logic, which usually runs during an arch_initcall() long
1025 * before any i2c_adapter could exist.
1026 *
1027 * This returns the new i2c client, which may be saved for later use with
1028 * i2c_unregister_device(); or NULL to indicate an error.
1029 */
1030struct i2c_client *
1031i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
1032{
1033 struct i2c_client *client;
1034 int status;
1035
1036 client = kzalloc(sizeof *client, GFP_KERNEL);
1037 if (!client)
1038 return NULL;
1039
1040 client->adapter = adap;
1041
1042 client->dev.platform_data = info->platform_data;
1043
1044 if (info->archdata)
1045 client->dev.archdata = *info->archdata;
1046
1047 client->flags = info->flags;
1048 client->addr = info->addr;
1049 client->irq = info->irq;
1050
1051 strlcpy(client->name, info->type, sizeof(client->name));
1052
1053 status = i2c_check_addr_validity(client->addr, client->flags);
1054 if (status) {
1055 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
1056 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
1057 goto out_err_silent;
1058 }
1059
1060 /* Check for address business */
1061 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
1062 if (status)
1063 goto out_err;
1064
1065 client->dev.parent = &client->adapter->dev;
1066 client->dev.bus = &i2c_bus_type;
1067 client->dev.type = &i2c_client_type;
1068 client->dev.of_node = info->of_node;
1069 client->dev.fwnode = info->fwnode;
1070
1071 i2c_dev_set_name(adap, client);
1072 status = device_register(&client->dev);
1073 if (status)
1074 goto out_err;
1075
1076 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
1077 client->name, dev_name(&client->dev));
1078
1079 return client;
1080
1081out_err:
1082 dev_err(&adap->dev, "Failed to register i2c client %s at 0x%02x "
1083 "(%d)\n", client->name, client->addr, status);
1084out_err_silent:
1085 kfree(client);
1086 return NULL;
1087}
1088EXPORT_SYMBOL_GPL(i2c_new_device);
1089
1090
1091/**
1092 * i2c_unregister_device - reverse effect of i2c_new_device()
1093 * @client: value returned from i2c_new_device()
1094 * Context: can sleep
1095 */
1096void i2c_unregister_device(struct i2c_client *client)
1097{
1098 if (client->dev.of_node)
1099 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
1100 device_unregister(&client->dev);
1101}
1102EXPORT_SYMBOL_GPL(i2c_unregister_device);
1103
1104
1105static const struct i2c_device_id dummy_id[] = {
1106 { "dummy", 0 },
1107 { },
1108};
1109
1110static int dummy_probe(struct i2c_client *client,
1111 const struct i2c_device_id *id)
1112{
1113 return 0;
1114}
1115
1116static int dummy_remove(struct i2c_client *client)
1117{
1118 return 0;
1119}
1120
1121static struct i2c_driver dummy_driver = {
1122 .driver.name = "dummy",
1123 .probe = dummy_probe,
1124 .remove = dummy_remove,
1125 .id_table = dummy_id,
1126};
1127
1128/**
1129 * i2c_new_dummy - return a new i2c device bound to a dummy driver
1130 * @adapter: the adapter managing the device
1131 * @address: seven bit address to be used
1132 * Context: can sleep
1133 *
1134 * This returns an I2C client bound to the "dummy" driver, intended for use
1135 * with devices that consume multiple addresses. Examples of such chips
1136 * include various EEPROMS (like 24c04 and 24c08 models).
1137 *
1138 * These dummy devices have two main uses. First, most I2C and SMBus calls
1139 * except i2c_transfer() need a client handle; the dummy will be that handle.
1140 * And second, this prevents the specified address from being bound to a
1141 * different driver.
1142 *
1143 * This returns the new i2c client, which should be saved for later use with
1144 * i2c_unregister_device(); or NULL to indicate an error.
1145 */
1146struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
1147{
1148 struct i2c_board_info info = {
1149 I2C_BOARD_INFO("dummy", address),
1150 };
1151
1152 return i2c_new_device(adapter, &info);
1153}
1154EXPORT_SYMBOL_GPL(i2c_new_dummy);
1155
1156/* ------------------------------------------------------------------------- */
1157
1158/* I2C bus adapters -- one roots each I2C or SMBUS segment */
1159
1160static void i2c_adapter_dev_release(struct device *dev)
1161{
1162 struct i2c_adapter *adap = to_i2c_adapter(dev);
1163 complete(&adap->dev_released);
1164}
1165
1166/*
1167 * This function is only needed for mutex_lock_nested, so it is never
1168 * called unless locking correctness checking is enabled. Thus we
1169 * make it inline to avoid a compiler warning. That's what gcc ends up
1170 * doing anyway.
1171 */
1172static inline unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1173{
1174 unsigned int depth = 0;
1175
1176 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
1177 depth++;
1178
1179 return depth;
1180}
1181
1182/*
1183 * Let users instantiate I2C devices through sysfs. This can be used when
1184 * platform initialization code doesn't contain the proper data for
1185 * whatever reason. Also useful for drivers that do device detection and
1186 * detection fails, either because the device uses an unexpected address,
1187 * or this is a compatible device with different ID register values.
1188 *
1189 * Parameter checking may look overzealous, but we really don't want
1190 * the user to provide incorrect parameters.
1191 */
1192static ssize_t
1193i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
1194 const char *buf, size_t count)
1195{
1196 struct i2c_adapter *adap = to_i2c_adapter(dev);
1197 struct i2c_board_info info;
1198 struct i2c_client *client;
1199 char *blank, end;
1200 int res;
1201
1202 memset(&info, 0, sizeof(struct i2c_board_info));
1203
1204 blank = strchr(buf, ' ');
1205 if (!blank) {
1206 dev_err(dev, "%s: Missing parameters\n", "new_device");
1207 return -EINVAL;
1208 }
1209 if (blank - buf > I2C_NAME_SIZE - 1) {
1210 dev_err(dev, "%s: Invalid device name\n", "new_device");
1211 return -EINVAL;
1212 }
1213 memcpy(info.type, buf, blank - buf);
1214
1215 /* Parse remaining parameters, reject extra parameters */
1216 res = sscanf(++blank, "%hi%c", &info.addr, &end);
1217 if (res < 1) {
1218 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1219 return -EINVAL;
1220 }
1221 if (res > 1 && end != '\n') {
1222 dev_err(dev, "%s: Extra parameters\n", "new_device");
1223 return -EINVAL;
1224 }
1225
1226 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1227 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1228 info.flags |= I2C_CLIENT_TEN;
1229 }
1230
1231 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1232 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1233 info.flags |= I2C_CLIENT_SLAVE;
1234 }
1235
1236 client = i2c_new_device(adap, &info);
1237 if (!client)
1238 return -EINVAL;
1239
1240 /* Keep track of the added device */
1241 mutex_lock(&adap->userspace_clients_lock);
1242 list_add_tail(&client->detected, &adap->userspace_clients);
1243 mutex_unlock(&adap->userspace_clients_lock);
1244 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1245 info.type, info.addr);
1246
1247 return count;
1248}
1249static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1250
1251/*
1252 * And of course let the users delete the devices they instantiated, if
1253 * they got it wrong. This interface can only be used to delete devices
1254 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1255 * don't delete devices to which some kernel code still has references.
1256 *
1257 * Parameter checking may look overzealous, but we really don't want
1258 * the user to delete the wrong device.
1259 */
1260static ssize_t
1261i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1262 const char *buf, size_t count)
1263{
1264 struct i2c_adapter *adap = to_i2c_adapter(dev);
1265 struct i2c_client *client, *next;
1266 unsigned short addr;
1267 char end;
1268 int res;
1269
1270 /* Parse parameters, reject extra parameters */
1271 res = sscanf(buf, "%hi%c", &addr, &end);
1272 if (res < 1) {
1273 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1274 return -EINVAL;
1275 }
1276 if (res > 1 && end != '\n') {
1277 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1278 return -EINVAL;
1279 }
1280
1281 /* Make sure the device was added through sysfs */
1282 res = -ENOENT;
1283 mutex_lock_nested(&adap->userspace_clients_lock,
1284 i2c_adapter_depth(adap));
1285 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1286 detected) {
1287 if (i2c_encode_flags_to_addr(client) == addr) {
1288 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1289 "delete_device", client->name, client->addr);
1290
1291 list_del(&client->detected);
1292 i2c_unregister_device(client);
1293 res = count;
1294 break;
1295 }
1296 }
1297 mutex_unlock(&adap->userspace_clients_lock);
1298
1299 if (res < 0)
1300 dev_err(dev, "%s: Can't find device in list\n",
1301 "delete_device");
1302 return res;
1303}
1304static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1305 i2c_sysfs_delete_device);
1306
1307static struct attribute *i2c_adapter_attrs[] = {
1308 &dev_attr_name.attr,
1309 &dev_attr_new_device.attr,
1310 &dev_attr_delete_device.attr,
1311 NULL
1312};
1313ATTRIBUTE_GROUPS(i2c_adapter);
1314
1315struct device_type i2c_adapter_type = {
1316 .groups = i2c_adapter_groups,
1317 .release = i2c_adapter_dev_release,
1318};
1319EXPORT_SYMBOL_GPL(i2c_adapter_type);
1320
1321/**
1322 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1323 * @dev: device, probably from some driver model iterator
1324 *
1325 * When traversing the driver model tree, perhaps using driver model
1326 * iterators like @device_for_each_child(), you can't assume very much
1327 * about the nodes you find. Use this function to avoid oopses caused
1328 * by wrongly treating some non-I2C device as an i2c_adapter.
1329 */
1330struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1331{
1332 return (dev->type == &i2c_adapter_type)
1333 ? to_i2c_adapter(dev)
1334 : NULL;
1335}
1336EXPORT_SYMBOL(i2c_verify_adapter);
1337
1338#ifdef CONFIG_I2C_COMPAT
1339static struct class_compat *i2c_adapter_compat_class;
1340#endif
1341
1342static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1343{
1344 struct i2c_devinfo *devinfo;
1345
1346 down_read(&__i2c_board_lock);
1347 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1348 if (devinfo->busnum == adapter->nr
1349 && !i2c_new_device(adapter,
1350 &devinfo->board_info))
1351 dev_err(&adapter->dev,
1352 "Can't create device at 0x%02x\n",
1353 devinfo->board_info.addr);
1354 }
1355 up_read(&__i2c_board_lock);
1356}
1357
1358/* OF support code */
1359
1360#if IS_ENABLED(CONFIG_OF)
1361static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
1362 struct device_node *node)
1363{
1364 struct i2c_client *result;
1365 struct i2c_board_info info = {};
1366 struct dev_archdata dev_ad = {};
1367 const __be32 *addr_be;
1368 u32 addr;
1369 int len;
1370
1371 dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
1372
1373 if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
1374 dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
1375 node->full_name);
1376 return ERR_PTR(-EINVAL);
1377 }
1378
1379 addr_be = of_get_property(node, "reg", &len);
1380 if (!addr_be || (len < sizeof(*addr_be))) {
1381 dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
1382 node->full_name);
1383 return ERR_PTR(-EINVAL);
1384 }
1385
1386 addr = be32_to_cpup(addr_be);
1387 if (addr & I2C_TEN_BIT_ADDRESS) {
1388 addr &= ~I2C_TEN_BIT_ADDRESS;
1389 info.flags |= I2C_CLIENT_TEN;
1390 }
1391
1392 if (addr & I2C_OWN_SLAVE_ADDRESS) {
1393 addr &= ~I2C_OWN_SLAVE_ADDRESS;
1394 info.flags |= I2C_CLIENT_SLAVE;
1395 }
1396
1397 if (i2c_check_addr_validity(addr, info.flags)) {
1398 dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
1399 info.addr, node->full_name);
1400 return ERR_PTR(-EINVAL);
1401 }
1402
1403 info.addr = addr;
1404 info.of_node = of_node_get(node);
1405 info.archdata = &dev_ad;
1406
1407 if (of_get_property(node, "wakeup-source", NULL))
1408 info.flags |= I2C_CLIENT_WAKE;
1409
1410 result = i2c_new_device(adap, &info);
1411 if (result == NULL) {
1412 dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
1413 node->full_name);
1414 of_node_put(node);
1415 return ERR_PTR(-EINVAL);
1416 }
1417 return result;
1418}
1419
1420static void of_i2c_register_devices(struct i2c_adapter *adap)
1421{
1422 struct device_node *node;
1423
1424 /* Only register child devices if the adapter has a node pointer set */
1425 if (!adap->dev.of_node)
1426 return;
1427
1428 dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
1429
1430 for_each_available_child_of_node(adap->dev.of_node, node) {
1431 if (of_node_test_and_set_flag(node, OF_POPULATED))
1432 continue;
1433 of_i2c_register_device(adap, node);
1434 }
1435}
1436
1437static int of_dev_node_match(struct device *dev, void *data)
1438{
1439 return dev->of_node == data;
1440}
1441
1442/* must call put_device() when done with returned i2c_client device */
1443struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
1444{
1445 struct device *dev;
1446 struct i2c_client *client;
1447
1448 dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
1449 if (!dev)
1450 return NULL;
1451
1452 client = i2c_verify_client(dev);
1453 if (!client)
1454 put_device(dev);
1455
1456 return client;
1457}
1458EXPORT_SYMBOL(of_find_i2c_device_by_node);
1459
1460/* must call put_device() when done with returned i2c_adapter device */
1461struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
1462{
1463 struct device *dev;
1464 struct i2c_adapter *adapter;
1465
1466 dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
1467 if (!dev)
1468 return NULL;
1469
1470 adapter = i2c_verify_adapter(dev);
1471 if (!adapter)
1472 put_device(dev);
1473
1474 return adapter;
1475}
1476EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
1477
1478/* must call i2c_put_adapter() when done with returned i2c_adapter device */
1479struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
1480{
1481 struct i2c_adapter *adapter;
1482
1483 adapter = of_find_i2c_adapter_by_node(node);
1484 if (!adapter)
1485 return NULL;
1486
1487 if (!try_module_get(adapter->owner)) {
1488 put_device(&adapter->dev);
1489 adapter = NULL;
1490 }
1491
1492 return adapter;
1493}
1494EXPORT_SYMBOL(of_get_i2c_adapter_by_node);
1495#else
1496static void of_i2c_register_devices(struct i2c_adapter *adap) { }
1497#endif /* CONFIG_OF */
1498
1499static int i2c_do_add_adapter(struct i2c_driver *driver,
1500 struct i2c_adapter *adap)
1501{
1502 /* Detect supported devices on that bus, and instantiate them */
1503 i2c_detect(adap, driver);
1504
1505 /* Let legacy drivers scan this bus for matching devices */
1506 if (driver->attach_adapter) {
1507 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1508 driver->driver.name);
1509 dev_warn(&adap->dev, "Please use another way to instantiate "
1510 "your i2c_client\n");
1511 /* We ignore the return code; if it fails, too bad */
1512 driver->attach_adapter(adap);
1513 }
1514 return 0;
1515}
1516
1517static int __process_new_adapter(struct device_driver *d, void *data)
1518{
1519 return i2c_do_add_adapter(to_i2c_driver(d), data);
1520}
1521
1522static int i2c_register_adapter(struct i2c_adapter *adap)
1523{
1524 int res = 0;
1525
1526 /* Can't register until after driver model init */
1527 if (WARN_ON(!is_registered)) {
1528 res = -EAGAIN;
1529 goto out_list;
1530 }
1531
1532 /* Sanity checks */
1533 if (unlikely(adap->name[0] == '\0')) {
1534 pr_err("i2c-core: Attempt to register an adapter with "
1535 "no name!\n");
1536 return -EINVAL;
1537 }
1538 if (unlikely(!adap->algo)) {
1539 pr_err("i2c-core: Attempt to register adapter '%s' with "
1540 "no algo!\n", adap->name);
1541 return -EINVAL;
1542 }
1543
1544 rt_mutex_init(&adap->bus_lock);
1545 mutex_init(&adap->userspace_clients_lock);
1546 INIT_LIST_HEAD(&adap->userspace_clients);
1547
1548 /* Set default timeout to 1 second if not already set */
1549 if (adap->timeout == 0)
1550 adap->timeout = HZ;
1551
1552 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1553 adap->dev.bus = &i2c_bus_type;
1554 adap->dev.type = &i2c_adapter_type;
1555 res = device_register(&adap->dev);
1556 if (res)
1557 goto out_list;
1558
1559 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1560
1561 pm_runtime_no_callbacks(&adap->dev);
1562 pm_runtime_enable(&adap->dev);
1563
1564#ifdef CONFIG_I2C_COMPAT
1565 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1566 adap->dev.parent);
1567 if (res)
1568 dev_warn(&adap->dev,
1569 "Failed to create compatibility class link\n");
1570#endif
1571
1572 /* bus recovery specific initialization */
1573 if (adap->bus_recovery_info) {
1574 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
1575
1576 if (!bri->recover_bus) {
1577 dev_err(&adap->dev, "No recover_bus() found, not using recovery\n");
1578 adap->bus_recovery_info = NULL;
1579 goto exit_recovery;
1580 }
1581
1582 /* Generic GPIO recovery */
1583 if (bri->recover_bus == i2c_generic_gpio_recovery) {
1584 if (!gpio_is_valid(bri->scl_gpio)) {
1585 dev_err(&adap->dev, "Invalid SCL gpio, not using recovery\n");
1586 adap->bus_recovery_info = NULL;
1587 goto exit_recovery;
1588 }
1589
1590 if (gpio_is_valid(bri->sda_gpio))
1591 bri->get_sda = get_sda_gpio_value;
1592 else
1593 bri->get_sda = NULL;
1594
1595 bri->get_scl = get_scl_gpio_value;
1596 bri->set_scl = set_scl_gpio_value;
1597 } else if (!bri->set_scl || !bri->get_scl) {
1598 /* Generic SCL recovery */
1599 dev_err(&adap->dev, "No {get|set}_gpio() found, not using recovery\n");
1600 adap->bus_recovery_info = NULL;
1601 }
1602 }
1603
1604exit_recovery:
1605 /* create pre-declared device nodes */
1606 of_i2c_register_devices(adap);
1607 acpi_i2c_register_devices(adap);
1608 acpi_i2c_install_space_handler(adap);
1609
1610 if (adap->nr < __i2c_first_dynamic_bus_num)
1611 i2c_scan_static_board_info(adap);
1612
1613 /* Notify drivers */
1614 mutex_lock(&core_lock);
1615 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1616 mutex_unlock(&core_lock);
1617
1618 return 0;
1619
1620out_list:
1621 mutex_lock(&core_lock);
1622 idr_remove(&i2c_adapter_idr, adap->nr);
1623 mutex_unlock(&core_lock);
1624 return res;
1625}
1626
1627/**
1628 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1629 * @adap: the adapter to register (with adap->nr initialized)
1630 * Context: can sleep
1631 *
1632 * See i2c_add_numbered_adapter() for details.
1633 */
1634static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1635{
1636 int id;
1637
1638 mutex_lock(&core_lock);
1639 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1,
1640 GFP_KERNEL);
1641 mutex_unlock(&core_lock);
1642 if (id < 0)
1643 return id == -ENOSPC ? -EBUSY : id;
1644
1645 return i2c_register_adapter(adap);
1646}
1647
1648/**
1649 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1650 * @adapter: the adapter to add
1651 * Context: can sleep
1652 *
1653 * This routine is used to declare an I2C adapter when its bus number
1654 * doesn't matter or when its bus number is specified by an dt alias.
1655 * Examples of bases when the bus number doesn't matter: I2C adapters
1656 * dynamically added by USB links or PCI plugin cards.
1657 *
1658 * When this returns zero, a new bus number was allocated and stored
1659 * in adap->nr, and the specified adapter became available for clients.
1660 * Otherwise, a negative errno value is returned.
1661 */
1662int i2c_add_adapter(struct i2c_adapter *adapter)
1663{
1664 struct device *dev = &adapter->dev;
1665 int id;
1666
1667 if (dev->of_node) {
1668 id = of_alias_get_id(dev->of_node, "i2c");
1669 if (id >= 0) {
1670 adapter->nr = id;
1671 return __i2c_add_numbered_adapter(adapter);
1672 }
1673 }
1674
1675 mutex_lock(&core_lock);
1676 id = idr_alloc(&i2c_adapter_idr, adapter,
1677 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1678 mutex_unlock(&core_lock);
1679 if (id < 0)
1680 return id;
1681
1682 adapter->nr = id;
1683
1684 return i2c_register_adapter(adapter);
1685}
1686EXPORT_SYMBOL(i2c_add_adapter);
1687
1688/**
1689 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1690 * @adap: the adapter to register (with adap->nr initialized)
1691 * Context: can sleep
1692 *
1693 * This routine is used to declare an I2C adapter when its bus number
1694 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1695 * or otherwise built in to the system's mainboard, and where i2c_board_info
1696 * is used to properly configure I2C devices.
1697 *
1698 * If the requested bus number is set to -1, then this function will behave
1699 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1700 *
1701 * If no devices have pre-been declared for this bus, then be sure to
1702 * register the adapter before any dynamically allocated ones. Otherwise
1703 * the required bus ID may not be available.
1704 *
1705 * When this returns zero, the specified adapter became available for
1706 * clients using the bus number provided in adap->nr. Also, the table
1707 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1708 * and the appropriate driver model device nodes are created. Otherwise, a
1709 * negative errno value is returned.
1710 */
1711int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1712{
1713 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1714 return i2c_add_adapter(adap);
1715
1716 return __i2c_add_numbered_adapter(adap);
1717}
1718EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1719
1720static void i2c_do_del_adapter(struct i2c_driver *driver,
1721 struct i2c_adapter *adapter)
1722{
1723 struct i2c_client *client, *_n;
1724
1725 /* Remove the devices we created ourselves as the result of hardware
1726 * probing (using a driver's detect method) */
1727 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1728 if (client->adapter == adapter) {
1729 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1730 client->name, client->addr);
1731 list_del(&client->detected);
1732 i2c_unregister_device(client);
1733 }
1734 }
1735}
1736
1737static int __unregister_client(struct device *dev, void *dummy)
1738{
1739 struct i2c_client *client = i2c_verify_client(dev);
1740 if (client && strcmp(client->name, "dummy"))
1741 i2c_unregister_device(client);
1742 return 0;
1743}
1744
1745static int __unregister_dummy(struct device *dev, void *dummy)
1746{
1747 struct i2c_client *client = i2c_verify_client(dev);
1748 if (client)
1749 i2c_unregister_device(client);
1750 return 0;
1751}
1752
1753static int __process_removed_adapter(struct device_driver *d, void *data)
1754{
1755 i2c_do_del_adapter(to_i2c_driver(d), data);
1756 return 0;
1757}
1758
1759/**
1760 * i2c_del_adapter - unregister I2C adapter
1761 * @adap: the adapter being unregistered
1762 * Context: can sleep
1763 *
1764 * This unregisters an I2C adapter which was previously registered
1765 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1766 */
1767void i2c_del_adapter(struct i2c_adapter *adap)
1768{
1769 struct i2c_adapter *found;
1770 struct i2c_client *client, *next;
1771
1772 /* First make sure that this adapter was ever added */
1773 mutex_lock(&core_lock);
1774 found = idr_find(&i2c_adapter_idr, adap->nr);
1775 mutex_unlock(&core_lock);
1776 if (found != adap) {
1777 pr_debug("i2c-core: attempting to delete unregistered "
1778 "adapter [%s]\n", adap->name);
1779 return;
1780 }
1781
1782 acpi_i2c_remove_space_handler(adap);
1783 /* Tell drivers about this removal */
1784 mutex_lock(&core_lock);
1785 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1786 __process_removed_adapter);
1787 mutex_unlock(&core_lock);
1788
1789 /* Remove devices instantiated from sysfs */
1790 mutex_lock_nested(&adap->userspace_clients_lock,
1791 i2c_adapter_depth(adap));
1792 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1793 detected) {
1794 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1795 client->addr);
1796 list_del(&client->detected);
1797 i2c_unregister_device(client);
1798 }
1799 mutex_unlock(&adap->userspace_clients_lock);
1800
1801 /* Detach any active clients. This can't fail, thus we do not
1802 * check the returned value. This is a two-pass process, because
1803 * we can't remove the dummy devices during the first pass: they
1804 * could have been instantiated by real devices wishing to clean
1805 * them up properly, so we give them a chance to do that first. */
1806 device_for_each_child(&adap->dev, NULL, __unregister_client);
1807 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1808
1809#ifdef CONFIG_I2C_COMPAT
1810 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1811 adap->dev.parent);
1812#endif
1813
1814 /* device name is gone after device_unregister */
1815 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1816
1817 pm_runtime_disable(&adap->dev);
1818
1819 /* wait until all references to the device are gone
1820 *
1821 * FIXME: This is old code and should ideally be replaced by an
1822 * alternative which results in decoupling the lifetime of the struct
1823 * device from the i2c_adapter, like spi or netdev do. Any solution
1824 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1825 */
1826 init_completion(&adap->dev_released);
1827 device_unregister(&adap->dev);
1828 wait_for_completion(&adap->dev_released);
1829
1830 /* free bus id */
1831 mutex_lock(&core_lock);
1832 idr_remove(&i2c_adapter_idr, adap->nr);
1833 mutex_unlock(&core_lock);
1834
1835 /* Clear the device structure in case this adapter is ever going to be
1836 added again */
1837 memset(&adap->dev, 0, sizeof(adap->dev));
1838}
1839EXPORT_SYMBOL(i2c_del_adapter);
1840
1841/**
1842 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1843 * @dev: The device to scan for I2C timing properties
1844 * @t: the i2c_timings struct to be filled with values
1845 * @use_defaults: bool to use sane defaults derived from the I2C specification
1846 * when properties are not found, otherwise use 0
1847 *
1848 * Scan the device for the generic I2C properties describing timing parameters
1849 * for the signal and fill the given struct with the results. If a property was
1850 * not found and use_defaults was true, then maximum timings are assumed which
1851 * are derived from the I2C specification. If use_defaults is not used, the
1852 * results will be 0, so drivers can apply their own defaults later. The latter
1853 * is mainly intended for avoiding regressions of existing drivers which want
1854 * to switch to this function. New drivers almost always should use the defaults.
1855 */
1856
1857void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1858{
1859 int ret;
1860
1861 memset(t, 0, sizeof(*t));
1862
1863 ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1864 if (ret && use_defaults)
1865 t->bus_freq_hz = 100000;
1866
1867 ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1868 if (ret && use_defaults) {
1869 if (t->bus_freq_hz <= 100000)
1870 t->scl_rise_ns = 1000;
1871 else if (t->bus_freq_hz <= 400000)
1872 t->scl_rise_ns = 300;
1873 else
1874 t->scl_rise_ns = 120;
1875 }
1876
1877 ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1878 if (ret && use_defaults) {
1879 if (t->bus_freq_hz <= 400000)
1880 t->scl_fall_ns = 300;
1881 else
1882 t->scl_fall_ns = 120;
1883 }
1884
1885 device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1886
1887 ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1888 if (ret && use_defaults)
1889 t->sda_fall_ns = t->scl_fall_ns;
1890}
1891EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1892
1893/* ------------------------------------------------------------------------- */
1894
1895int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1896{
1897 int res;
1898
1899 mutex_lock(&core_lock);
1900 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1901 mutex_unlock(&core_lock);
1902
1903 return res;
1904}
1905EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1906
1907static int __process_new_driver(struct device *dev, void *data)
1908{
1909 if (dev->type != &i2c_adapter_type)
1910 return 0;
1911 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1912}
1913
1914/*
1915 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1916 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1917 */
1918
1919int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1920{
1921 int res;
1922
1923 /* Can't register until after driver model init */
1924 if (WARN_ON(!is_registered))
1925 return -EAGAIN;
1926
1927 /* add the driver to the list of i2c drivers in the driver core */
1928 driver->driver.owner = owner;
1929 driver->driver.bus = &i2c_bus_type;
1930
1931 /* When registration returns, the driver core
1932 * will have called probe() for all matching-but-unbound devices.
1933 */
1934 res = driver_register(&driver->driver);
1935 if (res)
1936 return res;
1937
1938 pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
1939
1940 INIT_LIST_HEAD(&driver->clients);
1941 /* Walk the adapters that are already present */
1942 i2c_for_each_dev(driver, __process_new_driver);
1943
1944 return 0;
1945}
1946EXPORT_SYMBOL(i2c_register_driver);
1947
1948static int __process_removed_driver(struct device *dev, void *data)
1949{
1950 if (dev->type == &i2c_adapter_type)
1951 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1952 return 0;
1953}
1954
1955/**
1956 * i2c_del_driver - unregister I2C driver
1957 * @driver: the driver being unregistered
1958 * Context: can sleep
1959 */
1960void i2c_del_driver(struct i2c_driver *driver)
1961{
1962 i2c_for_each_dev(driver, __process_removed_driver);
1963
1964 driver_unregister(&driver->driver);
1965 pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);
1966}
1967EXPORT_SYMBOL(i2c_del_driver);
1968
1969/* ------------------------------------------------------------------------- */
1970
1971/**
1972 * i2c_use_client - increments the reference count of the i2c client structure
1973 * @client: the client being referenced
1974 *
1975 * Each live reference to a client should be refcounted. The driver model does
1976 * that automatically as part of driver binding, so that most drivers don't
1977 * need to do this explicitly: they hold a reference until they're unbound
1978 * from the device.
1979 *
1980 * A pointer to the client with the incremented reference counter is returned.
1981 */
1982struct i2c_client *i2c_use_client(struct i2c_client *client)
1983{
1984 if (client && get_device(&client->dev))
1985 return client;
1986 return NULL;
1987}
1988EXPORT_SYMBOL(i2c_use_client);
1989
1990/**
1991 * i2c_release_client - release a use of the i2c client structure
1992 * @client: the client being no longer referenced
1993 *
1994 * Must be called when a user of a client is finished with it.
1995 */
1996void i2c_release_client(struct i2c_client *client)
1997{
1998 if (client)
1999 put_device(&client->dev);
2000}
2001EXPORT_SYMBOL(i2c_release_client);
2002
2003struct i2c_cmd_arg {
2004 unsigned cmd;
2005 void *arg;
2006};
2007
2008static int i2c_cmd(struct device *dev, void *_arg)
2009{
2010 struct i2c_client *client = i2c_verify_client(dev);
2011 struct i2c_cmd_arg *arg = _arg;
2012 struct i2c_driver *driver;
2013
2014 if (!client || !client->dev.driver)
2015 return 0;
2016
2017 driver = to_i2c_driver(client->dev.driver);
2018 if (driver->command)
2019 driver->command(client, arg->cmd, arg->arg);
2020 return 0;
2021}
2022
2023void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
2024{
2025 struct i2c_cmd_arg cmd_arg;
2026
2027 cmd_arg.cmd = cmd;
2028 cmd_arg.arg = arg;
2029 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
2030}
2031EXPORT_SYMBOL(i2c_clients_command);
2032
2033#if IS_ENABLED(CONFIG_OF_DYNAMIC)
2034static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
2035 void *arg)
2036{
2037 struct of_reconfig_data *rd = arg;
2038 struct i2c_adapter *adap;
2039 struct i2c_client *client;
2040
2041 switch (of_reconfig_get_state_change(action, rd)) {
2042 case OF_RECONFIG_CHANGE_ADD:
2043 adap = of_find_i2c_adapter_by_node(rd->dn->parent);
2044 if (adap == NULL)
2045 return NOTIFY_OK; /* not for us */
2046
2047 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
2048 put_device(&adap->dev);
2049 return NOTIFY_OK;
2050 }
2051
2052 client = of_i2c_register_device(adap, rd->dn);
2053 put_device(&adap->dev);
2054
2055 if (IS_ERR(client)) {
2056 pr_err("%s: failed to create for '%s'\n",
2057 __func__, rd->dn->full_name);
2058 return notifier_from_errno(PTR_ERR(client));
2059 }
2060 break;
2061 case OF_RECONFIG_CHANGE_REMOVE:
2062 /* already depopulated? */
2063 if (!of_node_check_flag(rd->dn, OF_POPULATED))
2064 return NOTIFY_OK;
2065
2066 /* find our device by node */
2067 client = of_find_i2c_device_by_node(rd->dn);
2068 if (client == NULL)
2069 return NOTIFY_OK; /* no? not meant for us */
2070
2071 /* unregister takes one ref away */
2072 i2c_unregister_device(client);
2073
2074 /* and put the reference of the find */
2075 put_device(&client->dev);
2076 break;
2077 }
2078
2079 return NOTIFY_OK;
2080}
2081static struct notifier_block i2c_of_notifier = {
2082 .notifier_call = of_i2c_notify,
2083};
2084#else
2085extern struct notifier_block i2c_of_notifier;
2086#endif /* CONFIG_OF_DYNAMIC */
2087
2088static int __init i2c_init(void)
2089{
2090 int retval;
2091
2092 retval = of_alias_get_highest_id("i2c");
2093
2094 down_write(&__i2c_board_lock);
2095 if (retval >= __i2c_first_dynamic_bus_num)
2096 __i2c_first_dynamic_bus_num = retval + 1;
2097 up_write(&__i2c_board_lock);
2098
2099 retval = bus_register(&i2c_bus_type);
2100 if (retval)
2101 return retval;
2102
2103 is_registered = true;
2104
2105#ifdef CONFIG_I2C_COMPAT
2106 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
2107 if (!i2c_adapter_compat_class) {
2108 retval = -ENOMEM;
2109 goto bus_err;
2110 }
2111#endif
2112 retval = i2c_add_driver(&dummy_driver);
2113 if (retval)
2114 goto class_err;
2115
2116 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2117 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
2118
2119 return 0;
2120
2121class_err:
2122#ifdef CONFIG_I2C_COMPAT
2123 class_compat_unregister(i2c_adapter_compat_class);
2124bus_err:
2125#endif
2126 is_registered = false;
2127 bus_unregister(&i2c_bus_type);
2128 return retval;
2129}
2130
2131static void __exit i2c_exit(void)
2132{
2133 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2134 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2135 i2c_del_driver(&dummy_driver);
2136#ifdef CONFIG_I2C_COMPAT
2137 class_compat_unregister(i2c_adapter_compat_class);
2138#endif
2139 bus_unregister(&i2c_bus_type);
2140 tracepoint_synchronize_unregister();
2141}
2142
2143/* We must initialize early, because some subsystems register i2c drivers
2144 * in subsys_initcall() code, but are linked (and initialized) before i2c.
2145 */
2146postcore_initcall(i2c_init);
2147module_exit(i2c_exit);
2148
2149/* ----------------------------------------------------
2150 * the functional interface to the i2c busses.
2151 * ----------------------------------------------------
2152 */
2153
2154/* Check if val is exceeding the quirk IFF quirk is non 0 */
2155#define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
2156
2157static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
2158{
2159 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
2160 err_msg, msg->addr, msg->len,
2161 msg->flags & I2C_M_RD ? "read" : "write");
2162 return -EOPNOTSUPP;
2163}
2164
2165static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2166{
2167 const struct i2c_adapter_quirks *q = adap->quirks;
2168 int max_num = q->max_num_msgs, i;
2169 bool do_len_check = true;
2170
2171 if (q->flags & I2C_AQ_COMB) {
2172 max_num = 2;
2173
2174 /* special checks for combined messages */
2175 if (num == 2) {
2176 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
2177 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
2178
2179 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
2180 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
2181
2182 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
2183 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
2184
2185 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
2186 return i2c_quirk_error(adap, &msgs[0], "msg too long");
2187
2188 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
2189 return i2c_quirk_error(adap, &msgs[1], "msg too long");
2190
2191 do_len_check = false;
2192 }
2193 }
2194
2195 if (i2c_quirk_exceeded(num, max_num))
2196 return i2c_quirk_error(adap, &msgs[0], "too many messages");
2197
2198 for (i = 0; i < num; i++) {
2199 u16 len = msgs[i].len;
2200
2201 if (msgs[i].flags & I2C_M_RD) {
2202 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
2203 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2204 } else {
2205 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
2206 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2207 }
2208 }
2209
2210 return 0;
2211}
2212
2213/**
2214 * __i2c_transfer - unlocked flavor of i2c_transfer
2215 * @adap: Handle to I2C bus
2216 * @msgs: One or more messages to execute before STOP is issued to
2217 * terminate the operation; each message begins with a START.
2218 * @num: Number of messages to be executed.
2219 *
2220 * Returns negative errno, else the number of messages executed.
2221 *
2222 * Adapter lock must be held when calling this function. No debug logging
2223 * takes place. adap->algo->master_xfer existence isn't checked.
2224 */
2225int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2226{
2227 unsigned long orig_jiffies;
2228 int ret, try;
2229
2230 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2231 return -EOPNOTSUPP;
2232
2233 /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
2234 * enabled. This is an efficient way of keeping the for-loop from
2235 * being executed when not needed.
2236 */
2237 if (static_key_false(&i2c_trace_msg)) {
2238 int i;
2239 for (i = 0; i < num; i++)
2240 if (msgs[i].flags & I2C_M_RD)
2241 trace_i2c_read(adap, &msgs[i], i);
2242 else
2243 trace_i2c_write(adap, &msgs[i], i);
2244 }
2245
2246 /* Retry automatically on arbitration loss */
2247 orig_jiffies = jiffies;
2248 for (ret = 0, try = 0; try <= adap->retries; try++) {
2249 ret = adap->algo->master_xfer(adap, msgs, num);
2250 if (ret != -EAGAIN)
2251 break;
2252 if (time_after(jiffies, orig_jiffies + adap->timeout))
2253 break;
2254 }
2255
2256 if (static_key_false(&i2c_trace_msg)) {
2257 int i;
2258 for (i = 0; i < ret; i++)
2259 if (msgs[i].flags & I2C_M_RD)
2260 trace_i2c_reply(adap, &msgs[i], i);
2261 trace_i2c_result(adap, i, ret);
2262 }
2263
2264 return ret;
2265}
2266EXPORT_SYMBOL(__i2c_transfer);
2267
2268/**
2269 * i2c_transfer - execute a single or combined I2C message
2270 * @adap: Handle to I2C bus
2271 * @msgs: One or more messages to execute before STOP is issued to
2272 * terminate the operation; each message begins with a START.
2273 * @num: Number of messages to be executed.
2274 *
2275 * Returns negative errno, else the number of messages executed.
2276 *
2277 * Note that there is no requirement that each message be sent to
2278 * the same slave address, although that is the most common model.
2279 */
2280int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2281{
2282 int ret;
2283
2284 /* REVISIT the fault reporting model here is weak:
2285 *
2286 * - When we get an error after receiving N bytes from a slave,
2287 * there is no way to report "N".
2288 *
2289 * - When we get a NAK after transmitting N bytes to a slave,
2290 * there is no way to report "N" ... or to let the master
2291 * continue executing the rest of this combined message, if
2292 * that's the appropriate response.
2293 *
2294 * - When for example "num" is two and we successfully complete
2295 * the first message but get an error part way through the
2296 * second, it's unclear whether that should be reported as
2297 * one (discarding status on the second message) or errno
2298 * (discarding status on the first one).
2299 */
2300
2301 if (adap->algo->master_xfer) {
2302#ifdef DEBUG
2303 for (ret = 0; ret < num; ret++) {
2304 dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
2305 "len=%d%s\n", ret, (msgs[ret].flags & I2C_M_RD)
2306 ? 'R' : 'W', msgs[ret].addr, msgs[ret].len,
2307 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
2308 }
2309#endif
2310
2311 if (in_atomic() || irqs_disabled()) {
2312 ret = i2c_trylock_adapter(adap);
2313 if (!ret)
2314 /* I2C activity is ongoing. */
2315 return -EAGAIN;
2316 } else {
2317 i2c_lock_adapter(adap);
2318 }
2319
2320 ret = __i2c_transfer(adap, msgs, num);
2321 i2c_unlock_adapter(adap);
2322
2323 return ret;
2324 } else {
2325 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2326 return -EOPNOTSUPP;
2327 }
2328}
2329EXPORT_SYMBOL(i2c_transfer);
2330
2331/**
2332 * i2c_master_send - issue a single I2C message in master transmit mode
2333 * @client: Handle to slave device
2334 * @buf: Data that will be written to the slave
2335 * @count: How many bytes to write, must be less than 64k since msg.len is u16
2336 *
2337 * Returns negative errno, or else the number of bytes written.
2338 */
2339int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
2340{
2341 int ret;
2342 struct i2c_adapter *adap = client->adapter;
2343 struct i2c_msg msg;
2344
2345 msg.addr = client->addr;
2346 msg.flags = client->flags & I2C_M_TEN;
2347 msg.len = count;
2348 msg.buf = (char *)buf;
2349
2350 ret = i2c_transfer(adap, &msg, 1);
2351
2352 /*
2353 * If everything went ok (i.e. 1 msg transmitted), return #bytes
2354 * transmitted, else error code.
2355 */
2356 return (ret == 1) ? count : ret;
2357}
2358EXPORT_SYMBOL(i2c_master_send);
2359
2360/**
2361 * i2c_master_recv - issue a single I2C message in master receive mode
2362 * @client: Handle to slave device
2363 * @buf: Where to store data read from slave
2364 * @count: How many bytes to read, must be less than 64k since msg.len is u16
2365 *
2366 * Returns negative errno, or else the number of bytes read.
2367 */
2368int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
2369{
2370 struct i2c_adapter *adap = client->adapter;
2371 struct i2c_msg msg;
2372 int ret;
2373
2374 msg.addr = client->addr;
2375 msg.flags = client->flags & I2C_M_TEN;
2376 msg.flags |= I2C_M_RD;
2377 msg.len = count;
2378 msg.buf = buf;
2379
2380 ret = i2c_transfer(adap, &msg, 1);
2381
2382 /*
2383 * If everything went ok (i.e. 1 msg received), return #bytes received,
2384 * else error code.
2385 */
2386 return (ret == 1) ? count : ret;
2387}
2388EXPORT_SYMBOL(i2c_master_recv);
2389
2390/* ----------------------------------------------------
2391 * the i2c address scanning function
2392 * Will not work for 10-bit addresses!
2393 * ----------------------------------------------------
2394 */
2395
2396/*
2397 * Legacy default probe function, mostly relevant for SMBus. The default
2398 * probe method is a quick write, but it is known to corrupt the 24RF08
2399 * EEPROMs due to a state machine bug, and could also irreversibly
2400 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2401 * we use a short byte read instead. Also, some bus drivers don't implement
2402 * quick write, so we fallback to a byte read in that case too.
2403 * On x86, there is another special case for FSC hardware monitoring chips,
2404 * which want regular byte reads (address 0x73.) Fortunately, these are the
2405 * only known chips using this I2C address on PC hardware.
2406 * Returns 1 if probe succeeded, 0 if not.
2407 */
2408static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2409{
2410 int err;
2411 union i2c_smbus_data dummy;
2412
2413#ifdef CONFIG_X86
2414 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2415 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2416 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2417 I2C_SMBUS_BYTE_DATA, &dummy);
2418 else
2419#endif
2420 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2421 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2422 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2423 I2C_SMBUS_QUICK, NULL);
2424 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2425 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2426 I2C_SMBUS_BYTE, &dummy);
2427 else {
2428 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2429 addr);
2430 err = -EOPNOTSUPP;
2431 }
2432
2433 return err >= 0;
2434}
2435
2436static int i2c_detect_address(struct i2c_client *temp_client,
2437 struct i2c_driver *driver)
2438{
2439 struct i2c_board_info info;
2440 struct i2c_adapter *adapter = temp_client->adapter;
2441 int addr = temp_client->addr;
2442 int err;
2443
2444 /* Make sure the address is valid */
2445 err = i2c_check_7bit_addr_validity_strict(addr);
2446 if (err) {
2447 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2448 addr);
2449 return err;
2450 }
2451
2452 /* Skip if already in use (7 bit, no need to encode flags) */
2453 if (i2c_check_addr_busy(adapter, addr))
2454 return 0;
2455
2456 /* Make sure there is something at this address */
2457 if (!i2c_default_probe(adapter, addr))
2458 return 0;
2459
2460 /* Finally call the custom detection function */
2461 memset(&info, 0, sizeof(struct i2c_board_info));
2462 info.addr = addr;
2463 err = driver->detect(temp_client, &info);
2464 if (err) {
2465 /* -ENODEV is returned if the detection fails. We catch it
2466 here as this isn't an error. */
2467 return err == -ENODEV ? 0 : err;
2468 }
2469
2470 /* Consistency check */
2471 if (info.type[0] == '\0') {
2472 dev_err(&adapter->dev, "%s detection function provided "
2473 "no name for 0x%x\n", driver->driver.name,
2474 addr);
2475 } else {
2476 struct i2c_client *client;
2477
2478 /* Detection succeeded, instantiate the device */
2479 if (adapter->class & I2C_CLASS_DEPRECATED)
2480 dev_warn(&adapter->dev,
2481 "This adapter will soon drop class based instantiation of devices. "
2482 "Please make sure client 0x%02x gets instantiated by other means. "
2483 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2484 info.addr);
2485
2486 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2487 info.type, info.addr);
2488 client = i2c_new_device(adapter, &info);
2489 if (client)
2490 list_add_tail(&client->detected, &driver->clients);
2491 else
2492 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2493 info.type, info.addr);
2494 }
2495 return 0;
2496}
2497
2498static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2499{
2500 const unsigned short *address_list;
2501 struct i2c_client *temp_client;
2502 int i, err = 0;
2503 int adap_id = i2c_adapter_id(adapter);
2504
2505 address_list = driver->address_list;
2506 if (!driver->detect || !address_list)
2507 return 0;
2508
2509 /* Warn that the adapter lost class based instantiation */
2510 if (adapter->class == I2C_CLASS_DEPRECATED) {
2511 dev_dbg(&adapter->dev,
2512 "This adapter dropped support for I2C classes and "
2513 "won't auto-detect %s devices anymore. If you need it, check "
2514 "'Documentation/i2c/instantiating-devices' for alternatives.\n",
2515 driver->driver.name);
2516 return 0;
2517 }
2518
2519 /* Stop here if the classes do not match */
2520 if (!(adapter->class & driver->class))
2521 return 0;
2522
2523 /* Set up a temporary client to help detect callback */
2524 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2525 if (!temp_client)
2526 return -ENOMEM;
2527 temp_client->adapter = adapter;
2528
2529 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2530 dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
2531 "addr 0x%02x\n", adap_id, address_list[i]);
2532 temp_client->addr = address_list[i];
2533 err = i2c_detect_address(temp_client, driver);
2534 if (unlikely(err))
2535 break;
2536 }
2537
2538 kfree(temp_client);
2539 return err;
2540}
2541
2542int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2543{
2544 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2545 I2C_SMBUS_QUICK, NULL) >= 0;
2546}
2547EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2548
2549struct i2c_client *
2550i2c_new_probed_device(struct i2c_adapter *adap,
2551 struct i2c_board_info *info,
2552 unsigned short const *addr_list,
2553 int (*probe)(struct i2c_adapter *, unsigned short addr))
2554{
2555 int i;
2556
2557 if (!probe)
2558 probe = i2c_default_probe;
2559
2560 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2561 /* Check address validity */
2562 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2563 dev_warn(&adap->dev, "Invalid 7-bit address "
2564 "0x%02x\n", addr_list[i]);
2565 continue;
2566 }
2567
2568 /* Check address availability (7 bit, no need to encode flags) */
2569 if (i2c_check_addr_busy(adap, addr_list[i])) {
2570 dev_dbg(&adap->dev, "Address 0x%02x already in "
2571 "use, not probing\n", addr_list[i]);
2572 continue;
2573 }
2574
2575 /* Test address responsiveness */
2576 if (probe(adap, addr_list[i]))
2577 break;
2578 }
2579
2580 if (addr_list[i] == I2C_CLIENT_END) {
2581 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2582 return NULL;
2583 }
2584
2585 info->addr = addr_list[i];
2586 return i2c_new_device(adap, info);
2587}
2588EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2589
2590struct i2c_adapter *i2c_get_adapter(int nr)
2591{
2592 struct i2c_adapter *adapter;
2593
2594 mutex_lock(&core_lock);
2595 adapter = idr_find(&i2c_adapter_idr, nr);
2596 if (!adapter)
2597 goto exit;
2598
2599 if (try_module_get(adapter->owner))
2600 get_device(&adapter->dev);
2601 else
2602 adapter = NULL;
2603
2604 exit:
2605 mutex_unlock(&core_lock);
2606 return adapter;
2607}
2608EXPORT_SYMBOL(i2c_get_adapter);
2609
2610void i2c_put_adapter(struct i2c_adapter *adap)
2611{
2612 if (!adap)
2613 return;
2614
2615 put_device(&adap->dev);
2616 module_put(adap->owner);
2617}
2618EXPORT_SYMBOL(i2c_put_adapter);
2619
2620/* The SMBus parts */
2621
2622#define POLY (0x1070U << 3)
2623static u8 crc8(u16 data)
2624{
2625 int i;
2626
2627 for (i = 0; i < 8; i++) {
2628 if (data & 0x8000)
2629 data = data ^ POLY;
2630 data = data << 1;
2631 }
2632 return (u8)(data >> 8);
2633}
2634
2635/* Incremental CRC8 over count bytes in the array pointed to by p */
2636static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
2637{
2638 int i;
2639
2640 for (i = 0; i < count; i++)
2641 crc = crc8((crc ^ p[i]) << 8);
2642 return crc;
2643}
2644
2645/* Assume a 7-bit address, which is reasonable for SMBus */
2646static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
2647{
2648 /* The address will be sent first */
2649 u8 addr = (msg->addr << 1) | !!(msg->flags & I2C_M_RD);
2650 pec = i2c_smbus_pec(pec, &addr, 1);
2651
2652 /* The data buffer follows */
2653 return i2c_smbus_pec(pec, msg->buf, msg->len);
2654}
2655
2656/* Used for write only transactions */
2657static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
2658{
2659 msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
2660 msg->len++;
2661}
2662
2663/* Return <0 on CRC error
2664 If there was a write before this read (most cases) we need to take the
2665 partial CRC from the write part into account.
2666 Note that this function does modify the message (we need to decrease the
2667 message length to hide the CRC byte from the caller). */
2668static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
2669{
2670 u8 rpec = msg->buf[--msg->len];
2671 cpec = i2c_smbus_msg_pec(cpec, msg);
2672
2673 if (rpec != cpec) {
2674 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
2675 rpec, cpec);
2676 return -EBADMSG;
2677 }
2678 return 0;
2679}
2680
2681/**
2682 * i2c_smbus_read_byte - SMBus "receive byte" protocol
2683 * @client: Handle to slave device
2684 *
2685 * This executes the SMBus "receive byte" protocol, returning negative errno
2686 * else the byte received from the device.
2687 */
2688s32 i2c_smbus_read_byte(const struct i2c_client *client)
2689{
2690 union i2c_smbus_data data;
2691 int status;
2692
2693 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2694 I2C_SMBUS_READ, 0,
2695 I2C_SMBUS_BYTE, &data);
2696 return (status < 0) ? status : data.byte;
2697}
2698EXPORT_SYMBOL(i2c_smbus_read_byte);
2699
2700/**
2701 * i2c_smbus_write_byte - SMBus "send byte" protocol
2702 * @client: Handle to slave device
2703 * @value: Byte to be sent
2704 *
2705 * This executes the SMBus "send byte" protocol, returning negative errno
2706 * else zero on success.
2707 */
2708s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
2709{
2710 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2711 I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
2712}
2713EXPORT_SYMBOL(i2c_smbus_write_byte);
2714
2715/**
2716 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
2717 * @client: Handle to slave device
2718 * @command: Byte interpreted by slave
2719 *
2720 * This executes the SMBus "read byte" protocol, returning negative errno
2721 * else a data byte received from the device.
2722 */
2723s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command)
2724{
2725 union i2c_smbus_data data;
2726 int status;
2727
2728 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2729 I2C_SMBUS_READ, command,
2730 I2C_SMBUS_BYTE_DATA, &data);
2731 return (status < 0) ? status : data.byte;
2732}
2733EXPORT_SYMBOL(i2c_smbus_read_byte_data);
2734
2735/**
2736 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
2737 * @client: Handle to slave device
2738 * @command: Byte interpreted by slave
2739 * @value: Byte being written
2740 *
2741 * This executes the SMBus "write byte" protocol, returning negative errno
2742 * else zero on success.
2743 */
2744s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
2745 u8 value)
2746{
2747 union i2c_smbus_data data;
2748 data.byte = value;
2749 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2750 I2C_SMBUS_WRITE, command,
2751 I2C_SMBUS_BYTE_DATA, &data);
2752}
2753EXPORT_SYMBOL(i2c_smbus_write_byte_data);
2754
2755/**
2756 * i2c_smbus_read_word_data - SMBus "read word" protocol
2757 * @client: Handle to slave device
2758 * @command: Byte interpreted by slave
2759 *
2760 * This executes the SMBus "read word" protocol, returning negative errno
2761 * else a 16-bit unsigned "word" received from the device.
2762 */
2763s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
2764{
2765 union i2c_smbus_data data;
2766 int status;
2767
2768 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2769 I2C_SMBUS_READ, command,
2770 I2C_SMBUS_WORD_DATA, &data);
2771 return (status < 0) ? status : data.word;
2772}
2773EXPORT_SYMBOL(i2c_smbus_read_word_data);
2774
2775/**
2776 * i2c_smbus_write_word_data - SMBus "write word" protocol
2777 * @client: Handle to slave device
2778 * @command: Byte interpreted by slave
2779 * @value: 16-bit "word" being written
2780 *
2781 * This executes the SMBus "write word" protocol, returning negative errno
2782 * else zero on success.
2783 */
2784s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
2785 u16 value)
2786{
2787 union i2c_smbus_data data;
2788 data.word = value;
2789 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2790 I2C_SMBUS_WRITE, command,
2791 I2C_SMBUS_WORD_DATA, &data);
2792}
2793EXPORT_SYMBOL(i2c_smbus_write_word_data);
2794
2795/**
2796 * i2c_smbus_read_block_data - SMBus "block read" protocol
2797 * @client: Handle to slave device
2798 * @command: Byte interpreted by slave
2799 * @values: Byte array into which data will be read; big enough to hold
2800 * the data returned by the slave. SMBus allows at most 32 bytes.
2801 *
2802 * This executes the SMBus "block read" protocol, returning negative errno
2803 * else the number of data bytes in the slave's response.
2804 *
2805 * Note that using this function requires that the client's adapter support
2806 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
2807 * support this; its emulation through I2C messaging relies on a specific
2808 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
2809 */
2810s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
2811 u8 *values)
2812{
2813 union i2c_smbus_data data;
2814 int status;
2815
2816 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2817 I2C_SMBUS_READ, command,
2818 I2C_SMBUS_BLOCK_DATA, &data);
2819 if (status)
2820 return status;
2821
2822 memcpy(values, &data.block[1], data.block[0]);
2823 return data.block[0];
2824}
2825EXPORT_SYMBOL(i2c_smbus_read_block_data);
2826
2827/**
2828 * i2c_smbus_write_block_data - SMBus "block write" protocol
2829 * @client: Handle to slave device
2830 * @command: Byte interpreted by slave
2831 * @length: Size of data block; SMBus allows at most 32 bytes
2832 * @values: Byte array which will be written.
2833 *
2834 * This executes the SMBus "block write" protocol, returning negative errno
2835 * else zero on success.
2836 */
2837s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
2838 u8 length, const u8 *values)
2839{
2840 union i2c_smbus_data data;
2841
2842 if (length > I2C_SMBUS_BLOCK_MAX)
2843 length = I2C_SMBUS_BLOCK_MAX;
2844 data.block[0] = length;
2845 memcpy(&data.block[1], values, length);
2846 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2847 I2C_SMBUS_WRITE, command,
2848 I2C_SMBUS_BLOCK_DATA, &data);
2849}
2850EXPORT_SYMBOL(i2c_smbus_write_block_data);
2851
2852/* Returns the number of read bytes */
2853s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
2854 u8 length, u8 *values)
2855{
2856 union i2c_smbus_data data;
2857 int status;
2858
2859 if (length > I2C_SMBUS_BLOCK_MAX)
2860 length = I2C_SMBUS_BLOCK_MAX;
2861 data.block[0] = length;
2862 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2863 I2C_SMBUS_READ, command,
2864 I2C_SMBUS_I2C_BLOCK_DATA, &data);
2865 if (status < 0)
2866 return status;
2867
2868 memcpy(values, &data.block[1], data.block[0]);
2869 return data.block[0];
2870}
2871EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
2872
2873s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
2874 u8 length, const u8 *values)
2875{
2876 union i2c_smbus_data data;
2877
2878 if (length > I2C_SMBUS_BLOCK_MAX)
2879 length = I2C_SMBUS_BLOCK_MAX;
2880 data.block[0] = length;
2881 memcpy(data.block + 1, values, length);
2882 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2883 I2C_SMBUS_WRITE, command,
2884 I2C_SMBUS_I2C_BLOCK_DATA, &data);
2885}
2886EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
2887
2888/* Simulate a SMBus command using the i2c protocol
2889 No checking of parameters is done! */
2890static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
2891 unsigned short flags,
2892 char read_write, u8 command, int size,
2893 union i2c_smbus_data *data)
2894{
2895 /* So we need to generate a series of msgs. In the case of writing, we
2896 need to use only one message; when reading, we need two. We initialize
2897 most things with sane defaults, to keep the code below somewhat
2898 simpler. */
2899 unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
2900 unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
2901 int num = read_write == I2C_SMBUS_READ ? 2 : 1;
2902 int i;
2903 u8 partial_pec = 0;
2904 int status;
2905 struct i2c_msg msg[2] = {
2906 {
2907 .addr = addr,
2908 .flags = flags,
2909 .len = 1,
2910 .buf = msgbuf0,
2911 }, {
2912 .addr = addr,
2913 .flags = flags | I2C_M_RD,
2914 .len = 0,
2915 .buf = msgbuf1,
2916 },
2917 };
2918
2919 msgbuf0[0] = command;
2920 switch (size) {
2921 case I2C_SMBUS_QUICK:
2922 msg[0].len = 0;
2923 /* Special case: The read/write field is used as data */
2924 msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
2925 I2C_M_RD : 0);
2926 num = 1;
2927 break;
2928 case I2C_SMBUS_BYTE:
2929 if (read_write == I2C_SMBUS_READ) {
2930 /* Special case: only a read! */
2931 msg[0].flags = I2C_M_RD | flags;
2932 num = 1;
2933 }
2934 break;
2935 case I2C_SMBUS_BYTE_DATA:
2936 if (read_write == I2C_SMBUS_READ)
2937 msg[1].len = 1;
2938 else {
2939 msg[0].len = 2;
2940 msgbuf0[1] = data->byte;
2941 }
2942 break;
2943 case I2C_SMBUS_WORD_DATA:
2944 if (read_write == I2C_SMBUS_READ)
2945 msg[1].len = 2;
2946 else {
2947 msg[0].len = 3;
2948 msgbuf0[1] = data->word & 0xff;
2949 msgbuf0[2] = data->word >> 8;
2950 }
2951 break;
2952 case I2C_SMBUS_PROC_CALL:
2953 num = 2; /* Special case */
2954 read_write = I2C_SMBUS_READ;
2955 msg[0].len = 3;
2956 msg[1].len = 2;
2957 msgbuf0[1] = data->word & 0xff;
2958 msgbuf0[2] = data->word >> 8;
2959 break;
2960 case I2C_SMBUS_BLOCK_DATA:
2961 if (read_write == I2C_SMBUS_READ) {
2962 msg[1].flags |= I2C_M_RECV_LEN;
2963 msg[1].len = 1; /* block length will be added by
2964 the underlying bus driver */
2965 } else {
2966 msg[0].len = data->block[0] + 2;
2967 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
2968 dev_err(&adapter->dev,
2969 "Invalid block write size %d\n",
2970 data->block[0]);
2971 return -EINVAL;
2972 }
2973 for (i = 1; i < msg[0].len; i++)
2974 msgbuf0[i] = data->block[i-1];
2975 }
2976 break;
2977 case I2C_SMBUS_BLOCK_PROC_CALL:
2978 num = 2; /* Another special case */
2979 read_write = I2C_SMBUS_READ;
2980 if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
2981 dev_err(&adapter->dev,
2982 "Invalid block write size %d\n",
2983 data->block[0]);
2984 return -EINVAL;
2985 }
2986 msg[0].len = data->block[0] + 2;
2987 for (i = 1; i < msg[0].len; i++)
2988 msgbuf0[i] = data->block[i-1];
2989 msg[1].flags |= I2C_M_RECV_LEN;
2990 msg[1].len = 1; /* block length will be added by
2991 the underlying bus driver */
2992 break;
2993 case I2C_SMBUS_I2C_BLOCK_DATA:
2994 if (read_write == I2C_SMBUS_READ) {
2995 msg[1].len = data->block[0];
2996 } else {
2997 msg[0].len = data->block[0] + 1;
2998 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
2999 dev_err(&adapter->dev,
3000 "Invalid block write size %d\n",
3001 data->block[0]);
3002 return -EINVAL;
3003 }
3004 for (i = 1; i <= data->block[0]; i++)
3005 msgbuf0[i] = data->block[i];
3006 }
3007 break;
3008 default:
3009 dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
3010 return -EOPNOTSUPP;
3011 }
3012
3013 i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
3014 && size != I2C_SMBUS_I2C_BLOCK_DATA);
3015 if (i) {
3016 /* Compute PEC if first message is a write */
3017 if (!(msg[0].flags & I2C_M_RD)) {
3018 if (num == 1) /* Write only */
3019 i2c_smbus_add_pec(&msg[0]);
3020 else /* Write followed by read */
3021 partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
3022 }
3023 /* Ask for PEC if last message is a read */
3024 if (msg[num-1].flags & I2C_M_RD)
3025 msg[num-1].len++;
3026 }
3027
3028 status = i2c_transfer(adapter, msg, num);
3029 if (status < 0)
3030 return status;
3031
3032 /* Check PEC if last message is a read */
3033 if (i && (msg[num-1].flags & I2C_M_RD)) {
3034 status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
3035 if (status < 0)
3036 return status;
3037 }
3038
3039 if (read_write == I2C_SMBUS_READ)
3040 switch (size) {
3041 case I2C_SMBUS_BYTE:
3042 data->byte = msgbuf0[0];
3043 break;
3044 case I2C_SMBUS_BYTE_DATA:
3045 data->byte = msgbuf1[0];
3046 break;
3047 case I2C_SMBUS_WORD_DATA:
3048 case I2C_SMBUS_PROC_CALL:
3049 data->word = msgbuf1[0] | (msgbuf1[1] << 8);
3050 break;
3051 case I2C_SMBUS_I2C_BLOCK_DATA:
3052 for (i = 0; i < data->block[0]; i++)
3053 data->block[i+1] = msgbuf1[i];
3054 break;
3055 case I2C_SMBUS_BLOCK_DATA:
3056 case I2C_SMBUS_BLOCK_PROC_CALL:
3057 for (i = 0; i < msgbuf1[0] + 1; i++)
3058 data->block[i] = msgbuf1[i];
3059 break;
3060 }
3061 return 0;
3062}
3063
3064/**
3065 * i2c_smbus_xfer - execute SMBus protocol operations
3066 * @adapter: Handle to I2C bus
3067 * @addr: Address of SMBus slave on that bus
3068 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
3069 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
3070 * @command: Byte interpreted by slave, for protocols which use such bytes
3071 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
3072 * @data: Data to be read or written
3073 *
3074 * This executes an SMBus protocol operation, and returns a negative
3075 * errno code else zero on success.
3076 */
3077s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
3078 char read_write, u8 command, int protocol,
3079 union i2c_smbus_data *data)
3080{
3081 unsigned long orig_jiffies;
3082 int try;
3083 s32 res;
3084
3085 /* If enabled, the following two tracepoints are conditional on
3086 * read_write and protocol.
3087 */
3088 trace_smbus_write(adapter, addr, flags, read_write,
3089 command, protocol, data);
3090 trace_smbus_read(adapter, addr, flags, read_write,
3091 command, protocol);
3092
3093 flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
3094
3095 if (adapter->algo->smbus_xfer) {
3096 i2c_lock_adapter(adapter);
3097
3098 /* Retry automatically on arbitration loss */
3099 orig_jiffies = jiffies;
3100 for (res = 0, try = 0; try <= adapter->retries; try++) {
3101 res = adapter->algo->smbus_xfer(adapter, addr, flags,
3102 read_write, command,
3103 protocol, data);
3104 if (res != -EAGAIN)
3105 break;
3106 if (time_after(jiffies,
3107 orig_jiffies + adapter->timeout))
3108 break;
3109 }
3110 i2c_unlock_adapter(adapter);
3111
3112 if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
3113 goto trace;
3114 /*
3115 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
3116 * implement native support for the SMBus operation.
3117 */
3118 }
3119
3120 res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
3121 command, protocol, data);
3122
3123trace:
3124 /* If enabled, the reply tracepoint is conditional on read_write. */
3125 trace_smbus_reply(adapter, addr, flags, read_write,
3126 command, protocol, data);
3127 trace_smbus_result(adapter, addr, flags, read_write,
3128 command, protocol, res);
3129
3130 return res;
3131}
3132EXPORT_SYMBOL(i2c_smbus_xfer);
3133
3134/**
3135 * i2c_smbus_read_i2c_block_data_or_emulated - read block or emulate
3136 * @client: Handle to slave device
3137 * @command: Byte interpreted by slave
3138 * @length: Size of data block; SMBus allows at most I2C_SMBUS_BLOCK_MAX bytes
3139 * @values: Byte array into which data will be read; big enough to hold
3140 * the data returned by the slave. SMBus allows at most
3141 * I2C_SMBUS_BLOCK_MAX bytes.
3142 *
3143 * This executes the SMBus "block read" protocol if supported by the adapter.
3144 * If block read is not supported, it emulates it using either word or byte
3145 * read protocols depending on availability.
3146 *
3147 * The addresses of the I2C slave device that are accessed with this function
3148 * must be mapped to a linear region, so that a block read will have the same
3149 * effect as a byte read. Before using this function you must double-check
3150 * if the I2C slave does support exchanging a block transfer with a byte
3151 * transfer.
3152 */
3153s32 i2c_smbus_read_i2c_block_data_or_emulated(const struct i2c_client *client,
3154 u8 command, u8 length, u8 *values)
3155{
3156 u8 i = 0;
3157 int status;
3158
3159 if (length > I2C_SMBUS_BLOCK_MAX)
3160 length = I2C_SMBUS_BLOCK_MAX;
3161
3162 if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
3163 return i2c_smbus_read_i2c_block_data(client, command, length, values);
3164
3165 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA))
3166 return -EOPNOTSUPP;
3167
3168 if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_WORD_DATA)) {
3169 while ((i + 2) <= length) {
3170 status = i2c_smbus_read_word_data(client, command + i);
3171 if (status < 0)
3172 return status;
3173 values[i] = status & 0xff;
3174 values[i + 1] = status >> 8;
3175 i += 2;
3176 }
3177 }
3178
3179 while (i < length) {
3180 status = i2c_smbus_read_byte_data(client, command + i);
3181 if (status < 0)
3182 return status;
3183 values[i] = status;
3184 i++;
3185 }
3186
3187 return i;
3188}
3189EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data_or_emulated);
3190
3191#if IS_ENABLED(CONFIG_I2C_SLAVE)
3192int i2c_slave_register(struct i2c_client *client, i2c_slave_cb_t slave_cb)
3193{
3194 int ret;
3195
3196 if (!client || !slave_cb) {
3197 WARN(1, "insufficent data\n");
3198 return -EINVAL;
3199 }
3200
3201 if (!(client->flags & I2C_CLIENT_SLAVE))
3202 dev_warn(&client->dev, "%s: client slave flag not set. You might see address collisions\n",
3203 __func__);
3204
3205 if (!(client->flags & I2C_CLIENT_TEN)) {
3206 /* Enforce stricter address checking */
3207 ret = i2c_check_7bit_addr_validity_strict(client->addr);
3208 if (ret) {
3209 dev_err(&client->dev, "%s: invalid address\n", __func__);
3210 return ret;
3211 }
3212 }
3213
3214 if (!client->adapter->algo->reg_slave) {
3215 dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
3216 return -EOPNOTSUPP;
3217 }
3218
3219 client->slave_cb = slave_cb;
3220
3221 i2c_lock_adapter(client->adapter);
3222 ret = client->adapter->algo->reg_slave(client);
3223 i2c_unlock_adapter(client->adapter);
3224
3225 if (ret) {
3226 client->slave_cb = NULL;
3227 dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
3228 }
3229
3230 return ret;
3231}
3232EXPORT_SYMBOL_GPL(i2c_slave_register);
3233
3234int i2c_slave_unregister(struct i2c_client *client)
3235{
3236 int ret;
3237
3238 if (!client->adapter->algo->unreg_slave) {
3239 dev_err(&client->dev, "%s: not supported by adapter\n", __func__);
3240 return -EOPNOTSUPP;
3241 }
3242
3243 i2c_lock_adapter(client->adapter);
3244 ret = client->adapter->algo->unreg_slave(client);
3245 i2c_unlock_adapter(client->adapter);
3246
3247 if (ret == 0)
3248 client->slave_cb = NULL;
3249 else
3250 dev_err(&client->dev, "%s: adapter returned error %d\n", __func__, ret);
3251
3252 return ret;
3253}
3254EXPORT_SYMBOL_GPL(i2c_slave_unregister);
3255#endif
3256
3257MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
3258MODULE_DESCRIPTION("I2C-Bus main module");
3259MODULE_LICENSE("GPL");
1/* i2c-core.c - a device driver for the iic-bus interface */
2/* ------------------------------------------------------------------------- */
3/* Copyright (C) 1995-99 Simon G. Vogl
4
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
18 MA 02110-1301 USA. */
19/* ------------------------------------------------------------------------- */
20
21/* With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>.
22 All SMBus-related things are written by Frodo Looijaard <frodol@dds.nl>
23 SMBus 2.0 support by Mark Studebaker <mdsxyz123@yahoo.com> and
24 Jean Delvare <jdelvare@suse.de>
25 Mux support by Rodolfo Giometti <giometti@enneenne.com> and
26 Michael Lawnick <michael.lawnick.ext@nsn.com>
27 OF support is copyright (c) 2008 Jochen Friedrich <jochen@scram.de>
28 (based on a previous patch from Jon Smirl <jonsmirl@gmail.com>) and
29 (c) 2013 Wolfram Sang <wsa@the-dreams.de>
30 */
31
32#include <linux/module.h>
33#include <linux/kernel.h>
34#include <linux/delay.h>
35#include <linux/errno.h>
36#include <linux/gpio.h>
37#include <linux/slab.h>
38#include <linux/i2c.h>
39#include <linux/init.h>
40#include <linux/idr.h>
41#include <linux/mutex.h>
42#include <linux/of.h>
43#include <linux/of_device.h>
44#include <linux/of_irq.h>
45#include <linux/completion.h>
46#include <linux/hardirq.h>
47#include <linux/irqflags.h>
48#include <linux/rwsem.h>
49#include <linux/pm_runtime.h>
50#include <linux/acpi.h>
51#include <linux/jump_label.h>
52#include <asm/uaccess.h>
53
54#include "i2c-core.h"
55
56#define CREATE_TRACE_POINTS
57#include <trace/events/i2c.h>
58
59/* core_lock protects i2c_adapter_idr, and guarantees
60 that device detection, deletion of detected devices, and attach_adapter
61 calls are serialized */
62static DEFINE_MUTEX(core_lock);
63static DEFINE_IDR(i2c_adapter_idr);
64
65static struct device_type i2c_client_type;
66static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
67
68static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
69
70void i2c_transfer_trace_reg(void)
71{
72 static_key_slow_inc(&i2c_trace_msg);
73}
74
75void i2c_transfer_trace_unreg(void)
76{
77 static_key_slow_dec(&i2c_trace_msg);
78}
79
80/* ------------------------------------------------------------------------- */
81
82static const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
83 const struct i2c_client *client)
84{
85 while (id->name[0]) {
86 if (strcmp(client->name, id->name) == 0)
87 return id;
88 id++;
89 }
90 return NULL;
91}
92
93static int i2c_device_match(struct device *dev, struct device_driver *drv)
94{
95 struct i2c_client *client = i2c_verify_client(dev);
96 struct i2c_driver *driver;
97
98 if (!client)
99 return 0;
100
101 /* Attempt an OF style match */
102 if (of_driver_match_device(dev, drv))
103 return 1;
104
105 /* Then ACPI style match */
106 if (acpi_driver_match_device(dev, drv))
107 return 1;
108
109 driver = to_i2c_driver(drv);
110 /* match on an id table if there is one */
111 if (driver->id_table)
112 return i2c_match_id(driver->id_table, client) != NULL;
113
114 return 0;
115}
116
117
118/* uevent helps with hotplug: modprobe -q $(MODALIAS) */
119static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
120{
121 struct i2c_client *client = to_i2c_client(dev);
122 int rc;
123
124 rc = acpi_device_uevent_modalias(dev, env);
125 if (rc != -ENODEV)
126 return rc;
127
128 if (add_uevent_var(env, "MODALIAS=%s%s",
129 I2C_MODULE_PREFIX, client->name))
130 return -ENOMEM;
131 dev_dbg(dev, "uevent\n");
132 return 0;
133}
134
135/* i2c bus recovery routines */
136static int get_scl_gpio_value(struct i2c_adapter *adap)
137{
138 return gpio_get_value(adap->bus_recovery_info->scl_gpio);
139}
140
141static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
142{
143 gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
144}
145
146static int get_sda_gpio_value(struct i2c_adapter *adap)
147{
148 return gpio_get_value(adap->bus_recovery_info->sda_gpio);
149}
150
151static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
152{
153 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
154 struct device *dev = &adap->dev;
155 int ret = 0;
156
157 ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN |
158 GPIOF_OUT_INIT_HIGH, "i2c-scl");
159 if (ret) {
160 dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio);
161 return ret;
162 }
163
164 if (bri->get_sda) {
165 if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) {
166 /* work without SDA polling */
167 dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n",
168 bri->sda_gpio);
169 bri->get_sda = NULL;
170 }
171 }
172
173 return ret;
174}
175
176static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
177{
178 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
179
180 if (bri->get_sda)
181 gpio_free(bri->sda_gpio);
182
183 gpio_free(bri->scl_gpio);
184}
185
186/*
187 * We are generating clock pulses. ndelay() determines durating of clk pulses.
188 * We will generate clock with rate 100 KHz and so duration of both clock levels
189 * is: delay in ns = (10^6 / 100) / 2
190 */
191#define RECOVERY_NDELAY 5000
192#define RECOVERY_CLK_CNT 9
193
194static int i2c_generic_recovery(struct i2c_adapter *adap)
195{
196 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
197 int i = 0, val = 1, ret = 0;
198
199 if (bri->prepare_recovery)
200 bri->prepare_recovery(bri);
201
202 /*
203 * By this time SCL is high, as we need to give 9 falling-rising edges
204 */
205 while (i++ < RECOVERY_CLK_CNT * 2) {
206 if (val) {
207 /* Break if SDA is high */
208 if (bri->get_sda && bri->get_sda(adap))
209 break;
210 /* SCL shouldn't be low here */
211 if (!bri->get_scl(adap)) {
212 dev_err(&adap->dev,
213 "SCL is stuck low, exit recovery\n");
214 ret = -EBUSY;
215 break;
216 }
217 }
218
219 val = !val;
220 bri->set_scl(adap, val);
221 ndelay(RECOVERY_NDELAY);
222 }
223
224 if (bri->unprepare_recovery)
225 bri->unprepare_recovery(bri);
226
227 return ret;
228}
229
230int i2c_generic_scl_recovery(struct i2c_adapter *adap)
231{
232 adap->bus_recovery_info->set_scl(adap, 1);
233 return i2c_generic_recovery(adap);
234}
235
236int i2c_generic_gpio_recovery(struct i2c_adapter *adap)
237{
238 int ret;
239
240 ret = i2c_get_gpios_for_recovery(adap);
241 if (ret)
242 return ret;
243
244 ret = i2c_generic_recovery(adap);
245 i2c_put_gpios_for_recovery(adap);
246
247 return ret;
248}
249
250int i2c_recover_bus(struct i2c_adapter *adap)
251{
252 if (!adap->bus_recovery_info)
253 return -EOPNOTSUPP;
254
255 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
256 return adap->bus_recovery_info->recover_bus(adap);
257}
258
259static int i2c_device_probe(struct device *dev)
260{
261 struct i2c_client *client = i2c_verify_client(dev);
262 struct i2c_driver *driver;
263 int status;
264
265 if (!client)
266 return 0;
267
268 driver = to_i2c_driver(dev->driver);
269 if (!driver->probe || !driver->id_table)
270 return -ENODEV;
271
272 if (!device_can_wakeup(&client->dev))
273 device_init_wakeup(&client->dev,
274 client->flags & I2C_CLIENT_WAKE);
275 dev_dbg(dev, "probe\n");
276
277 acpi_dev_pm_attach(&client->dev, true);
278 status = driver->probe(client, i2c_match_id(driver->id_table, client));
279 if (status)
280 acpi_dev_pm_detach(&client->dev, true);
281
282 return status;
283}
284
285static int i2c_device_remove(struct device *dev)
286{
287 struct i2c_client *client = i2c_verify_client(dev);
288 struct i2c_driver *driver;
289 int status = 0;
290
291 if (!client || !dev->driver)
292 return 0;
293
294 driver = to_i2c_driver(dev->driver);
295 if (driver->remove) {
296 dev_dbg(dev, "remove\n");
297 status = driver->remove(client);
298 }
299
300 acpi_dev_pm_detach(&client->dev, true);
301 return status;
302}
303
304static void i2c_device_shutdown(struct device *dev)
305{
306 struct i2c_client *client = i2c_verify_client(dev);
307 struct i2c_driver *driver;
308
309 if (!client || !dev->driver)
310 return;
311 driver = to_i2c_driver(dev->driver);
312 if (driver->shutdown)
313 driver->shutdown(client);
314}
315
316#ifdef CONFIG_PM_SLEEP
317static int i2c_legacy_suspend(struct device *dev, pm_message_t mesg)
318{
319 struct i2c_client *client = i2c_verify_client(dev);
320 struct i2c_driver *driver;
321
322 if (!client || !dev->driver)
323 return 0;
324 driver = to_i2c_driver(dev->driver);
325 if (!driver->suspend)
326 return 0;
327 return driver->suspend(client, mesg);
328}
329
330static int i2c_legacy_resume(struct device *dev)
331{
332 struct i2c_client *client = i2c_verify_client(dev);
333 struct i2c_driver *driver;
334
335 if (!client || !dev->driver)
336 return 0;
337 driver = to_i2c_driver(dev->driver);
338 if (!driver->resume)
339 return 0;
340 return driver->resume(client);
341}
342
343static int i2c_device_pm_suspend(struct device *dev)
344{
345 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
346
347 if (pm)
348 return pm_generic_suspend(dev);
349 else
350 return i2c_legacy_suspend(dev, PMSG_SUSPEND);
351}
352
353static int i2c_device_pm_resume(struct device *dev)
354{
355 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
356
357 if (pm)
358 return pm_generic_resume(dev);
359 else
360 return i2c_legacy_resume(dev);
361}
362
363static int i2c_device_pm_freeze(struct device *dev)
364{
365 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
366
367 if (pm)
368 return pm_generic_freeze(dev);
369 else
370 return i2c_legacy_suspend(dev, PMSG_FREEZE);
371}
372
373static int i2c_device_pm_thaw(struct device *dev)
374{
375 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
376
377 if (pm)
378 return pm_generic_thaw(dev);
379 else
380 return i2c_legacy_resume(dev);
381}
382
383static int i2c_device_pm_poweroff(struct device *dev)
384{
385 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
386
387 if (pm)
388 return pm_generic_poweroff(dev);
389 else
390 return i2c_legacy_suspend(dev, PMSG_HIBERNATE);
391}
392
393static int i2c_device_pm_restore(struct device *dev)
394{
395 const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
396
397 if (pm)
398 return pm_generic_restore(dev);
399 else
400 return i2c_legacy_resume(dev);
401}
402#else /* !CONFIG_PM_SLEEP */
403#define i2c_device_pm_suspend NULL
404#define i2c_device_pm_resume NULL
405#define i2c_device_pm_freeze NULL
406#define i2c_device_pm_thaw NULL
407#define i2c_device_pm_poweroff NULL
408#define i2c_device_pm_restore NULL
409#endif /* !CONFIG_PM_SLEEP */
410
411static void i2c_client_dev_release(struct device *dev)
412{
413 kfree(to_i2c_client(dev));
414}
415
416static ssize_t
417show_name(struct device *dev, struct device_attribute *attr, char *buf)
418{
419 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
420 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
421}
422
423static ssize_t
424show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
425{
426 struct i2c_client *client = to_i2c_client(dev);
427 int len;
428
429 len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
430 if (len != -ENODEV)
431 return len;
432
433 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
434}
435
436static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
437static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
438
439static struct attribute *i2c_dev_attrs[] = {
440 &dev_attr_name.attr,
441 /* modalias helps coldplug: modprobe $(cat .../modalias) */
442 &dev_attr_modalias.attr,
443 NULL
444};
445
446static struct attribute_group i2c_dev_attr_group = {
447 .attrs = i2c_dev_attrs,
448};
449
450static const struct attribute_group *i2c_dev_attr_groups[] = {
451 &i2c_dev_attr_group,
452 NULL
453};
454
455static const struct dev_pm_ops i2c_device_pm_ops = {
456 .suspend = i2c_device_pm_suspend,
457 .resume = i2c_device_pm_resume,
458 .freeze = i2c_device_pm_freeze,
459 .thaw = i2c_device_pm_thaw,
460 .poweroff = i2c_device_pm_poweroff,
461 .restore = i2c_device_pm_restore,
462 SET_RUNTIME_PM_OPS(
463 pm_generic_runtime_suspend,
464 pm_generic_runtime_resume,
465 NULL
466 )
467};
468
469struct bus_type i2c_bus_type = {
470 .name = "i2c",
471 .match = i2c_device_match,
472 .probe = i2c_device_probe,
473 .remove = i2c_device_remove,
474 .shutdown = i2c_device_shutdown,
475 .pm = &i2c_device_pm_ops,
476};
477EXPORT_SYMBOL_GPL(i2c_bus_type);
478
479static struct device_type i2c_client_type = {
480 .groups = i2c_dev_attr_groups,
481 .uevent = i2c_device_uevent,
482 .release = i2c_client_dev_release,
483};
484
485
486/**
487 * i2c_verify_client - return parameter as i2c_client, or NULL
488 * @dev: device, probably from some driver model iterator
489 *
490 * When traversing the driver model tree, perhaps using driver model
491 * iterators like @device_for_each_child(), you can't assume very much
492 * about the nodes you find. Use this function to avoid oopses caused
493 * by wrongly treating some non-I2C device as an i2c_client.
494 */
495struct i2c_client *i2c_verify_client(struct device *dev)
496{
497 return (dev->type == &i2c_client_type)
498 ? to_i2c_client(dev)
499 : NULL;
500}
501EXPORT_SYMBOL(i2c_verify_client);
502
503
504/* This is a permissive address validity check, I2C address map constraints
505 * are purposely not enforced, except for the general call address. */
506static int i2c_check_client_addr_validity(const struct i2c_client *client)
507{
508 if (client->flags & I2C_CLIENT_TEN) {
509 /* 10-bit address, all values are valid */
510 if (client->addr > 0x3ff)
511 return -EINVAL;
512 } else {
513 /* 7-bit address, reject the general call address */
514 if (client->addr == 0x00 || client->addr > 0x7f)
515 return -EINVAL;
516 }
517 return 0;
518}
519
520/* And this is a strict address validity check, used when probing. If a
521 * device uses a reserved address, then it shouldn't be probed. 7-bit
522 * addressing is assumed, 10-bit address devices are rare and should be
523 * explicitly enumerated. */
524static int i2c_check_addr_validity(unsigned short addr)
525{
526 /*
527 * Reserved addresses per I2C specification:
528 * 0x00 General call address / START byte
529 * 0x01 CBUS address
530 * 0x02 Reserved for different bus format
531 * 0x03 Reserved for future purposes
532 * 0x04-0x07 Hs-mode master code
533 * 0x78-0x7b 10-bit slave addressing
534 * 0x7c-0x7f Reserved for future purposes
535 */
536 if (addr < 0x08 || addr > 0x77)
537 return -EINVAL;
538 return 0;
539}
540
541static int __i2c_check_addr_busy(struct device *dev, void *addrp)
542{
543 struct i2c_client *client = i2c_verify_client(dev);
544 int addr = *(int *)addrp;
545
546 if (client && client->addr == addr)
547 return -EBUSY;
548 return 0;
549}
550
551/* walk up mux tree */
552static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
553{
554 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
555 int result;
556
557 result = device_for_each_child(&adapter->dev, &addr,
558 __i2c_check_addr_busy);
559
560 if (!result && parent)
561 result = i2c_check_mux_parents(parent, addr);
562
563 return result;
564}
565
566/* recurse down mux tree */
567static int i2c_check_mux_children(struct device *dev, void *addrp)
568{
569 int result;
570
571 if (dev->type == &i2c_adapter_type)
572 result = device_for_each_child(dev, addrp,
573 i2c_check_mux_children);
574 else
575 result = __i2c_check_addr_busy(dev, addrp);
576
577 return result;
578}
579
580static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
581{
582 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
583 int result = 0;
584
585 if (parent)
586 result = i2c_check_mux_parents(parent, addr);
587
588 if (!result)
589 result = device_for_each_child(&adapter->dev, &addr,
590 i2c_check_mux_children);
591
592 return result;
593}
594
595/**
596 * i2c_lock_adapter - Get exclusive access to an I2C bus segment
597 * @adapter: Target I2C bus segment
598 */
599void i2c_lock_adapter(struct i2c_adapter *adapter)
600{
601 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
602
603 if (parent)
604 i2c_lock_adapter(parent);
605 else
606 rt_mutex_lock(&adapter->bus_lock);
607}
608EXPORT_SYMBOL_GPL(i2c_lock_adapter);
609
610/**
611 * i2c_trylock_adapter - Try to get exclusive access to an I2C bus segment
612 * @adapter: Target I2C bus segment
613 */
614static int i2c_trylock_adapter(struct i2c_adapter *adapter)
615{
616 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
617
618 if (parent)
619 return i2c_trylock_adapter(parent);
620 else
621 return rt_mutex_trylock(&adapter->bus_lock);
622}
623
624/**
625 * i2c_unlock_adapter - Release exclusive access to an I2C bus segment
626 * @adapter: Target I2C bus segment
627 */
628void i2c_unlock_adapter(struct i2c_adapter *adapter)
629{
630 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
631
632 if (parent)
633 i2c_unlock_adapter(parent);
634 else
635 rt_mutex_unlock(&adapter->bus_lock);
636}
637EXPORT_SYMBOL_GPL(i2c_unlock_adapter);
638
639static void i2c_dev_set_name(struct i2c_adapter *adap,
640 struct i2c_client *client)
641{
642 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
643
644 if (adev) {
645 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
646 return;
647 }
648
649 /* For 10-bit clients, add an arbitrary offset to avoid collisions */
650 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
651 client->addr | ((client->flags & I2C_CLIENT_TEN)
652 ? 0xa000 : 0));
653}
654
655/**
656 * i2c_new_device - instantiate an i2c device
657 * @adap: the adapter managing the device
658 * @info: describes one I2C device; bus_num is ignored
659 * Context: can sleep
660 *
661 * Create an i2c device. Binding is handled through driver model
662 * probe()/remove() methods. A driver may be bound to this device when we
663 * return from this function, or any later moment (e.g. maybe hotplugging will
664 * load the driver module). This call is not appropriate for use by mainboard
665 * initialization logic, which usually runs during an arch_initcall() long
666 * before any i2c_adapter could exist.
667 *
668 * This returns the new i2c client, which may be saved for later use with
669 * i2c_unregister_device(); or NULL to indicate an error.
670 */
671struct i2c_client *
672i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
673{
674 struct i2c_client *client;
675 int status;
676
677 client = kzalloc(sizeof *client, GFP_KERNEL);
678 if (!client)
679 return NULL;
680
681 client->adapter = adap;
682
683 client->dev.platform_data = info->platform_data;
684
685 if (info->archdata)
686 client->dev.archdata = *info->archdata;
687
688 client->flags = info->flags;
689 client->addr = info->addr;
690 client->irq = info->irq;
691
692 strlcpy(client->name, info->type, sizeof(client->name));
693
694 /* Check for address validity */
695 status = i2c_check_client_addr_validity(client);
696 if (status) {
697 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
698 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
699 goto out_err_silent;
700 }
701
702 /* Check for address business */
703 status = i2c_check_addr_busy(adap, client->addr);
704 if (status)
705 goto out_err;
706
707 client->dev.parent = &client->adapter->dev;
708 client->dev.bus = &i2c_bus_type;
709 client->dev.type = &i2c_client_type;
710 client->dev.of_node = info->of_node;
711 ACPI_COMPANION_SET(&client->dev, info->acpi_node.companion);
712
713 i2c_dev_set_name(adap, client);
714 status = device_register(&client->dev);
715 if (status)
716 goto out_err;
717
718 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
719 client->name, dev_name(&client->dev));
720
721 return client;
722
723out_err:
724 dev_err(&adap->dev, "Failed to register i2c client %s at 0x%02x "
725 "(%d)\n", client->name, client->addr, status);
726out_err_silent:
727 kfree(client);
728 return NULL;
729}
730EXPORT_SYMBOL_GPL(i2c_new_device);
731
732
733/**
734 * i2c_unregister_device - reverse effect of i2c_new_device()
735 * @client: value returned from i2c_new_device()
736 * Context: can sleep
737 */
738void i2c_unregister_device(struct i2c_client *client)
739{
740 device_unregister(&client->dev);
741}
742EXPORT_SYMBOL_GPL(i2c_unregister_device);
743
744
745static const struct i2c_device_id dummy_id[] = {
746 { "dummy", 0 },
747 { },
748};
749
750static int dummy_probe(struct i2c_client *client,
751 const struct i2c_device_id *id)
752{
753 return 0;
754}
755
756static int dummy_remove(struct i2c_client *client)
757{
758 return 0;
759}
760
761static struct i2c_driver dummy_driver = {
762 .driver.name = "dummy",
763 .probe = dummy_probe,
764 .remove = dummy_remove,
765 .id_table = dummy_id,
766};
767
768/**
769 * i2c_new_dummy - return a new i2c device bound to a dummy driver
770 * @adapter: the adapter managing the device
771 * @address: seven bit address to be used
772 * Context: can sleep
773 *
774 * This returns an I2C client bound to the "dummy" driver, intended for use
775 * with devices that consume multiple addresses. Examples of such chips
776 * include various EEPROMS (like 24c04 and 24c08 models).
777 *
778 * These dummy devices have two main uses. First, most I2C and SMBus calls
779 * except i2c_transfer() need a client handle; the dummy will be that handle.
780 * And second, this prevents the specified address from being bound to a
781 * different driver.
782 *
783 * This returns the new i2c client, which should be saved for later use with
784 * i2c_unregister_device(); or NULL to indicate an error.
785 */
786struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
787{
788 struct i2c_board_info info = {
789 I2C_BOARD_INFO("dummy", address),
790 };
791
792 return i2c_new_device(adapter, &info);
793}
794EXPORT_SYMBOL_GPL(i2c_new_dummy);
795
796/* ------------------------------------------------------------------------- */
797
798/* I2C bus adapters -- one roots each I2C or SMBUS segment */
799
800static void i2c_adapter_dev_release(struct device *dev)
801{
802 struct i2c_adapter *adap = to_i2c_adapter(dev);
803 complete(&adap->dev_released);
804}
805
806/*
807 * This function is only needed for mutex_lock_nested, so it is never
808 * called unless locking correctness checking is enabled. Thus we
809 * make it inline to avoid a compiler warning. That's what gcc ends up
810 * doing anyway.
811 */
812static inline unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
813{
814 unsigned int depth = 0;
815
816 while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
817 depth++;
818
819 return depth;
820}
821
822/*
823 * Let users instantiate I2C devices through sysfs. This can be used when
824 * platform initialization code doesn't contain the proper data for
825 * whatever reason. Also useful for drivers that do device detection and
826 * detection fails, either because the device uses an unexpected address,
827 * or this is a compatible device with different ID register values.
828 *
829 * Parameter checking may look overzealous, but we really don't want
830 * the user to provide incorrect parameters.
831 */
832static ssize_t
833i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
834 const char *buf, size_t count)
835{
836 struct i2c_adapter *adap = to_i2c_adapter(dev);
837 struct i2c_board_info info;
838 struct i2c_client *client;
839 char *blank, end;
840 int res;
841
842 memset(&info, 0, sizeof(struct i2c_board_info));
843
844 blank = strchr(buf, ' ');
845 if (!blank) {
846 dev_err(dev, "%s: Missing parameters\n", "new_device");
847 return -EINVAL;
848 }
849 if (blank - buf > I2C_NAME_SIZE - 1) {
850 dev_err(dev, "%s: Invalid device name\n", "new_device");
851 return -EINVAL;
852 }
853 memcpy(info.type, buf, blank - buf);
854
855 /* Parse remaining parameters, reject extra parameters */
856 res = sscanf(++blank, "%hi%c", &info.addr, &end);
857 if (res < 1) {
858 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
859 return -EINVAL;
860 }
861 if (res > 1 && end != '\n') {
862 dev_err(dev, "%s: Extra parameters\n", "new_device");
863 return -EINVAL;
864 }
865
866 client = i2c_new_device(adap, &info);
867 if (!client)
868 return -EINVAL;
869
870 /* Keep track of the added device */
871 mutex_lock(&adap->userspace_clients_lock);
872 list_add_tail(&client->detected, &adap->userspace_clients);
873 mutex_unlock(&adap->userspace_clients_lock);
874 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
875 info.type, info.addr);
876
877 return count;
878}
879
880/*
881 * And of course let the users delete the devices they instantiated, if
882 * they got it wrong. This interface can only be used to delete devices
883 * instantiated by i2c_sysfs_new_device above. This guarantees that we
884 * don't delete devices to which some kernel code still has references.
885 *
886 * Parameter checking may look overzealous, but we really don't want
887 * the user to delete the wrong device.
888 */
889static ssize_t
890i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
891 const char *buf, size_t count)
892{
893 struct i2c_adapter *adap = to_i2c_adapter(dev);
894 struct i2c_client *client, *next;
895 unsigned short addr;
896 char end;
897 int res;
898
899 /* Parse parameters, reject extra parameters */
900 res = sscanf(buf, "%hi%c", &addr, &end);
901 if (res < 1) {
902 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
903 return -EINVAL;
904 }
905 if (res > 1 && end != '\n') {
906 dev_err(dev, "%s: Extra parameters\n", "delete_device");
907 return -EINVAL;
908 }
909
910 /* Make sure the device was added through sysfs */
911 res = -ENOENT;
912 mutex_lock_nested(&adap->userspace_clients_lock,
913 i2c_adapter_depth(adap));
914 list_for_each_entry_safe(client, next, &adap->userspace_clients,
915 detected) {
916 if (client->addr == addr) {
917 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
918 "delete_device", client->name, client->addr);
919
920 list_del(&client->detected);
921 i2c_unregister_device(client);
922 res = count;
923 break;
924 }
925 }
926 mutex_unlock(&adap->userspace_clients_lock);
927
928 if (res < 0)
929 dev_err(dev, "%s: Can't find device in list\n",
930 "delete_device");
931 return res;
932}
933
934static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
935static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
936 i2c_sysfs_delete_device);
937
938static struct attribute *i2c_adapter_attrs[] = {
939 &dev_attr_name.attr,
940 &dev_attr_new_device.attr,
941 &dev_attr_delete_device.attr,
942 NULL
943};
944
945static struct attribute_group i2c_adapter_attr_group = {
946 .attrs = i2c_adapter_attrs,
947};
948
949static const struct attribute_group *i2c_adapter_attr_groups[] = {
950 &i2c_adapter_attr_group,
951 NULL
952};
953
954struct device_type i2c_adapter_type = {
955 .groups = i2c_adapter_attr_groups,
956 .release = i2c_adapter_dev_release,
957};
958EXPORT_SYMBOL_GPL(i2c_adapter_type);
959
960/**
961 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
962 * @dev: device, probably from some driver model iterator
963 *
964 * When traversing the driver model tree, perhaps using driver model
965 * iterators like @device_for_each_child(), you can't assume very much
966 * about the nodes you find. Use this function to avoid oopses caused
967 * by wrongly treating some non-I2C device as an i2c_adapter.
968 */
969struct i2c_adapter *i2c_verify_adapter(struct device *dev)
970{
971 return (dev->type == &i2c_adapter_type)
972 ? to_i2c_adapter(dev)
973 : NULL;
974}
975EXPORT_SYMBOL(i2c_verify_adapter);
976
977#ifdef CONFIG_I2C_COMPAT
978static struct class_compat *i2c_adapter_compat_class;
979#endif
980
981static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
982{
983 struct i2c_devinfo *devinfo;
984
985 down_read(&__i2c_board_lock);
986 list_for_each_entry(devinfo, &__i2c_board_list, list) {
987 if (devinfo->busnum == adapter->nr
988 && !i2c_new_device(adapter,
989 &devinfo->board_info))
990 dev_err(&adapter->dev,
991 "Can't create device at 0x%02x\n",
992 devinfo->board_info.addr);
993 }
994 up_read(&__i2c_board_lock);
995}
996
997/* OF support code */
998
999#if IS_ENABLED(CONFIG_OF)
1000static void of_i2c_register_devices(struct i2c_adapter *adap)
1001{
1002 void *result;
1003 struct device_node *node;
1004
1005 /* Only register child devices if the adapter has a node pointer set */
1006 if (!adap->dev.of_node)
1007 return;
1008
1009 dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
1010
1011 for_each_available_child_of_node(adap->dev.of_node, node) {
1012 struct i2c_board_info info = {};
1013 struct dev_archdata dev_ad = {};
1014 const __be32 *addr;
1015 int len;
1016
1017 dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
1018
1019 if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
1020 dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
1021 node->full_name);
1022 continue;
1023 }
1024
1025 addr = of_get_property(node, "reg", &len);
1026 if (!addr || (len < sizeof(int))) {
1027 dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
1028 node->full_name);
1029 continue;
1030 }
1031
1032 info.addr = be32_to_cpup(addr);
1033 if (info.addr > (1 << 10) - 1) {
1034 dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
1035 info.addr, node->full_name);
1036 continue;
1037 }
1038
1039 info.irq = irq_of_parse_and_map(node, 0);
1040 info.of_node = of_node_get(node);
1041 info.archdata = &dev_ad;
1042
1043 if (of_get_property(node, "wakeup-source", NULL))
1044 info.flags |= I2C_CLIENT_WAKE;
1045
1046 request_module("%s%s", I2C_MODULE_PREFIX, info.type);
1047
1048 result = i2c_new_device(adap, &info);
1049 if (result == NULL) {
1050 dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
1051 node->full_name);
1052 of_node_put(node);
1053 irq_dispose_mapping(info.irq);
1054 continue;
1055 }
1056 }
1057}
1058
1059static int of_dev_node_match(struct device *dev, void *data)
1060{
1061 return dev->of_node == data;
1062}
1063
1064/* must call put_device() when done with returned i2c_client device */
1065struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
1066{
1067 struct device *dev;
1068
1069 dev = bus_find_device(&i2c_bus_type, NULL, node,
1070 of_dev_node_match);
1071 if (!dev)
1072 return NULL;
1073
1074 return i2c_verify_client(dev);
1075}
1076EXPORT_SYMBOL(of_find_i2c_device_by_node);
1077
1078/* must call put_device() when done with returned i2c_adapter device */
1079struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
1080{
1081 struct device *dev;
1082
1083 dev = bus_find_device(&i2c_bus_type, NULL, node,
1084 of_dev_node_match);
1085 if (!dev)
1086 return NULL;
1087
1088 return i2c_verify_adapter(dev);
1089}
1090EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
1091#else
1092static void of_i2c_register_devices(struct i2c_adapter *adap) { }
1093#endif /* CONFIG_OF */
1094
1095/* ACPI support code */
1096
1097#if IS_ENABLED(CONFIG_ACPI)
1098static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
1099{
1100 struct i2c_board_info *info = data;
1101
1102 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1103 struct acpi_resource_i2c_serialbus *sb;
1104
1105 sb = &ares->data.i2c_serial_bus;
1106 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
1107 info->addr = sb->slave_address;
1108 if (sb->access_mode == ACPI_I2C_10BIT_MODE)
1109 info->flags |= I2C_CLIENT_TEN;
1110 }
1111 } else if (info->irq < 0) {
1112 struct resource r;
1113
1114 if (acpi_dev_resource_interrupt(ares, 0, &r))
1115 info->irq = r.start;
1116 }
1117
1118 /* Tell the ACPI core to skip this resource */
1119 return 1;
1120}
1121
1122static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
1123 void *data, void **return_value)
1124{
1125 struct i2c_adapter *adapter = data;
1126 struct list_head resource_list;
1127 struct i2c_board_info info;
1128 struct acpi_device *adev;
1129 int ret;
1130
1131 if (acpi_bus_get_device(handle, &adev))
1132 return AE_OK;
1133 if (acpi_bus_get_status(adev) || !adev->status.present)
1134 return AE_OK;
1135
1136 memset(&info, 0, sizeof(info));
1137 info.acpi_node.companion = adev;
1138 info.irq = -1;
1139
1140 INIT_LIST_HEAD(&resource_list);
1141 ret = acpi_dev_get_resources(adev, &resource_list,
1142 acpi_i2c_add_resource, &info);
1143 acpi_dev_free_resource_list(&resource_list);
1144
1145 if (ret < 0 || !info.addr)
1146 return AE_OK;
1147
1148 adev->power.flags.ignore_parent = true;
1149 strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
1150 if (!i2c_new_device(adapter, &info)) {
1151 adev->power.flags.ignore_parent = false;
1152 dev_err(&adapter->dev,
1153 "failed to add I2C device %s from ACPI\n",
1154 dev_name(&adev->dev));
1155 }
1156
1157 return AE_OK;
1158}
1159
1160/**
1161 * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
1162 * @adap: pointer to adapter
1163 *
1164 * Enumerate all I2C slave devices behind this adapter by walking the ACPI
1165 * namespace. When a device is found it will be added to the Linux device
1166 * model and bound to the corresponding ACPI handle.
1167 */
1168static void acpi_i2c_register_devices(struct i2c_adapter *adap)
1169{
1170 acpi_handle handle;
1171 acpi_status status;
1172
1173 if (!adap->dev.parent)
1174 return;
1175
1176 handle = ACPI_HANDLE(adap->dev.parent);
1177 if (!handle)
1178 return;
1179
1180 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1181 acpi_i2c_add_device, NULL,
1182 adap, NULL);
1183 if (ACPI_FAILURE(status))
1184 dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
1185}
1186#else
1187static inline void acpi_i2c_register_devices(struct i2c_adapter *adap) {}
1188#endif /* CONFIG_ACPI */
1189
1190static int i2c_do_add_adapter(struct i2c_driver *driver,
1191 struct i2c_adapter *adap)
1192{
1193 /* Detect supported devices on that bus, and instantiate them */
1194 i2c_detect(adap, driver);
1195
1196 /* Let legacy drivers scan this bus for matching devices */
1197 if (driver->attach_adapter) {
1198 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1199 driver->driver.name);
1200 dev_warn(&adap->dev, "Please use another way to instantiate "
1201 "your i2c_client\n");
1202 /* We ignore the return code; if it fails, too bad */
1203 driver->attach_adapter(adap);
1204 }
1205 return 0;
1206}
1207
1208static int __process_new_adapter(struct device_driver *d, void *data)
1209{
1210 return i2c_do_add_adapter(to_i2c_driver(d), data);
1211}
1212
1213static int i2c_register_adapter(struct i2c_adapter *adap)
1214{
1215 int res = 0;
1216
1217 /* Can't register until after driver model init */
1218 if (unlikely(WARN_ON(!i2c_bus_type.p))) {
1219 res = -EAGAIN;
1220 goto out_list;
1221 }
1222
1223 /* Sanity checks */
1224 if (unlikely(adap->name[0] == '\0')) {
1225 pr_err("i2c-core: Attempt to register an adapter with "
1226 "no name!\n");
1227 return -EINVAL;
1228 }
1229 if (unlikely(!adap->algo)) {
1230 pr_err("i2c-core: Attempt to register adapter '%s' with "
1231 "no algo!\n", adap->name);
1232 return -EINVAL;
1233 }
1234
1235 rt_mutex_init(&adap->bus_lock);
1236 mutex_init(&adap->userspace_clients_lock);
1237 INIT_LIST_HEAD(&adap->userspace_clients);
1238
1239 /* Set default timeout to 1 second if not already set */
1240 if (adap->timeout == 0)
1241 adap->timeout = HZ;
1242
1243 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1244 adap->dev.bus = &i2c_bus_type;
1245 adap->dev.type = &i2c_adapter_type;
1246 res = device_register(&adap->dev);
1247 if (res)
1248 goto out_list;
1249
1250 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1251
1252#ifdef CONFIG_I2C_COMPAT
1253 res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1254 adap->dev.parent);
1255 if (res)
1256 dev_warn(&adap->dev,
1257 "Failed to create compatibility class link\n");
1258#endif
1259
1260 /* bus recovery specific initialization */
1261 if (adap->bus_recovery_info) {
1262 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
1263
1264 if (!bri->recover_bus) {
1265 dev_err(&adap->dev, "No recover_bus() found, not using recovery\n");
1266 adap->bus_recovery_info = NULL;
1267 goto exit_recovery;
1268 }
1269
1270 /* Generic GPIO recovery */
1271 if (bri->recover_bus == i2c_generic_gpio_recovery) {
1272 if (!gpio_is_valid(bri->scl_gpio)) {
1273 dev_err(&adap->dev, "Invalid SCL gpio, not using recovery\n");
1274 adap->bus_recovery_info = NULL;
1275 goto exit_recovery;
1276 }
1277
1278 if (gpio_is_valid(bri->sda_gpio))
1279 bri->get_sda = get_sda_gpio_value;
1280 else
1281 bri->get_sda = NULL;
1282
1283 bri->get_scl = get_scl_gpio_value;
1284 bri->set_scl = set_scl_gpio_value;
1285 } else if (!bri->set_scl || !bri->get_scl) {
1286 /* Generic SCL recovery */
1287 dev_err(&adap->dev, "No {get|set}_gpio() found, not using recovery\n");
1288 adap->bus_recovery_info = NULL;
1289 }
1290 }
1291
1292exit_recovery:
1293 /* create pre-declared device nodes */
1294 of_i2c_register_devices(adap);
1295 acpi_i2c_register_devices(adap);
1296
1297 if (adap->nr < __i2c_first_dynamic_bus_num)
1298 i2c_scan_static_board_info(adap);
1299
1300 /* Notify drivers */
1301 mutex_lock(&core_lock);
1302 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1303 mutex_unlock(&core_lock);
1304
1305 return 0;
1306
1307out_list:
1308 mutex_lock(&core_lock);
1309 idr_remove(&i2c_adapter_idr, adap->nr);
1310 mutex_unlock(&core_lock);
1311 return res;
1312}
1313
1314/**
1315 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1316 * @adap: the adapter to register (with adap->nr initialized)
1317 * Context: can sleep
1318 *
1319 * See i2c_add_numbered_adapter() for details.
1320 */
1321static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1322{
1323 int id;
1324
1325 mutex_lock(&core_lock);
1326 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1,
1327 GFP_KERNEL);
1328 mutex_unlock(&core_lock);
1329 if (id < 0)
1330 return id == -ENOSPC ? -EBUSY : id;
1331
1332 return i2c_register_adapter(adap);
1333}
1334
1335/**
1336 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1337 * @adapter: the adapter to add
1338 * Context: can sleep
1339 *
1340 * This routine is used to declare an I2C adapter when its bus number
1341 * doesn't matter or when its bus number is specified by an dt alias.
1342 * Examples of bases when the bus number doesn't matter: I2C adapters
1343 * dynamically added by USB links or PCI plugin cards.
1344 *
1345 * When this returns zero, a new bus number was allocated and stored
1346 * in adap->nr, and the specified adapter became available for clients.
1347 * Otherwise, a negative errno value is returned.
1348 */
1349int i2c_add_adapter(struct i2c_adapter *adapter)
1350{
1351 struct device *dev = &adapter->dev;
1352 int id;
1353
1354 if (dev->of_node) {
1355 id = of_alias_get_id(dev->of_node, "i2c");
1356 if (id >= 0) {
1357 adapter->nr = id;
1358 return __i2c_add_numbered_adapter(adapter);
1359 }
1360 }
1361
1362 mutex_lock(&core_lock);
1363 id = idr_alloc(&i2c_adapter_idr, adapter,
1364 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1365 mutex_unlock(&core_lock);
1366 if (id < 0)
1367 return id;
1368
1369 adapter->nr = id;
1370
1371 return i2c_register_adapter(adapter);
1372}
1373EXPORT_SYMBOL(i2c_add_adapter);
1374
1375/**
1376 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1377 * @adap: the adapter to register (with adap->nr initialized)
1378 * Context: can sleep
1379 *
1380 * This routine is used to declare an I2C adapter when its bus number
1381 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1382 * or otherwise built in to the system's mainboard, and where i2c_board_info
1383 * is used to properly configure I2C devices.
1384 *
1385 * If the requested bus number is set to -1, then this function will behave
1386 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1387 *
1388 * If no devices have pre-been declared for this bus, then be sure to
1389 * register the adapter before any dynamically allocated ones. Otherwise
1390 * the required bus ID may not be available.
1391 *
1392 * When this returns zero, the specified adapter became available for
1393 * clients using the bus number provided in adap->nr. Also, the table
1394 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1395 * and the appropriate driver model device nodes are created. Otherwise, a
1396 * negative errno value is returned.
1397 */
1398int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1399{
1400 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1401 return i2c_add_adapter(adap);
1402
1403 return __i2c_add_numbered_adapter(adap);
1404}
1405EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1406
1407static void i2c_do_del_adapter(struct i2c_driver *driver,
1408 struct i2c_adapter *adapter)
1409{
1410 struct i2c_client *client, *_n;
1411
1412 /* Remove the devices we created ourselves as the result of hardware
1413 * probing (using a driver's detect method) */
1414 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1415 if (client->adapter == adapter) {
1416 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1417 client->name, client->addr);
1418 list_del(&client->detected);
1419 i2c_unregister_device(client);
1420 }
1421 }
1422}
1423
1424static int __unregister_client(struct device *dev, void *dummy)
1425{
1426 struct i2c_client *client = i2c_verify_client(dev);
1427 if (client && strcmp(client->name, "dummy"))
1428 i2c_unregister_device(client);
1429 return 0;
1430}
1431
1432static int __unregister_dummy(struct device *dev, void *dummy)
1433{
1434 struct i2c_client *client = i2c_verify_client(dev);
1435 if (client)
1436 i2c_unregister_device(client);
1437 return 0;
1438}
1439
1440static int __process_removed_adapter(struct device_driver *d, void *data)
1441{
1442 i2c_do_del_adapter(to_i2c_driver(d), data);
1443 return 0;
1444}
1445
1446/**
1447 * i2c_del_adapter - unregister I2C adapter
1448 * @adap: the adapter being unregistered
1449 * Context: can sleep
1450 *
1451 * This unregisters an I2C adapter which was previously registered
1452 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1453 */
1454void i2c_del_adapter(struct i2c_adapter *adap)
1455{
1456 struct i2c_adapter *found;
1457 struct i2c_client *client, *next;
1458
1459 /* First make sure that this adapter was ever added */
1460 mutex_lock(&core_lock);
1461 found = idr_find(&i2c_adapter_idr, adap->nr);
1462 mutex_unlock(&core_lock);
1463 if (found != adap) {
1464 pr_debug("i2c-core: attempting to delete unregistered "
1465 "adapter [%s]\n", adap->name);
1466 return;
1467 }
1468
1469 /* Tell drivers about this removal */
1470 mutex_lock(&core_lock);
1471 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1472 __process_removed_adapter);
1473 mutex_unlock(&core_lock);
1474
1475 /* Remove devices instantiated from sysfs */
1476 mutex_lock_nested(&adap->userspace_clients_lock,
1477 i2c_adapter_depth(adap));
1478 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1479 detected) {
1480 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1481 client->addr);
1482 list_del(&client->detected);
1483 i2c_unregister_device(client);
1484 }
1485 mutex_unlock(&adap->userspace_clients_lock);
1486
1487 /* Detach any active clients. This can't fail, thus we do not
1488 * check the returned value. This is a two-pass process, because
1489 * we can't remove the dummy devices during the first pass: they
1490 * could have been instantiated by real devices wishing to clean
1491 * them up properly, so we give them a chance to do that first. */
1492 device_for_each_child(&adap->dev, NULL, __unregister_client);
1493 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1494
1495#ifdef CONFIG_I2C_COMPAT
1496 class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1497 adap->dev.parent);
1498#endif
1499
1500 /* device name is gone after device_unregister */
1501 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1502
1503 /* clean up the sysfs representation */
1504 init_completion(&adap->dev_released);
1505 device_unregister(&adap->dev);
1506
1507 /* wait for sysfs to drop all references */
1508 wait_for_completion(&adap->dev_released);
1509
1510 /* free bus id */
1511 mutex_lock(&core_lock);
1512 idr_remove(&i2c_adapter_idr, adap->nr);
1513 mutex_unlock(&core_lock);
1514
1515 /* Clear the device structure in case this adapter is ever going to be
1516 added again */
1517 memset(&adap->dev, 0, sizeof(adap->dev));
1518}
1519EXPORT_SYMBOL(i2c_del_adapter);
1520
1521/* ------------------------------------------------------------------------- */
1522
1523int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1524{
1525 int res;
1526
1527 mutex_lock(&core_lock);
1528 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1529 mutex_unlock(&core_lock);
1530
1531 return res;
1532}
1533EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1534
1535static int __process_new_driver(struct device *dev, void *data)
1536{
1537 if (dev->type != &i2c_adapter_type)
1538 return 0;
1539 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1540}
1541
1542/*
1543 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1544 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1545 */
1546
1547int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1548{
1549 int res;
1550
1551 /* Can't register until after driver model init */
1552 if (unlikely(WARN_ON(!i2c_bus_type.p)))
1553 return -EAGAIN;
1554
1555 /* add the driver to the list of i2c drivers in the driver core */
1556 driver->driver.owner = owner;
1557 driver->driver.bus = &i2c_bus_type;
1558
1559 /* When registration returns, the driver core
1560 * will have called probe() for all matching-but-unbound devices.
1561 */
1562 res = driver_register(&driver->driver);
1563 if (res)
1564 return res;
1565
1566 /* Drivers should switch to dev_pm_ops instead. */
1567 if (driver->suspend)
1568 pr_warn("i2c-core: driver [%s] using legacy suspend method\n",
1569 driver->driver.name);
1570 if (driver->resume)
1571 pr_warn("i2c-core: driver [%s] using legacy resume method\n",
1572 driver->driver.name);
1573
1574 pr_debug("i2c-core: driver [%s] registered\n", driver->driver.name);
1575
1576 INIT_LIST_HEAD(&driver->clients);
1577 /* Walk the adapters that are already present */
1578 i2c_for_each_dev(driver, __process_new_driver);
1579
1580 return 0;
1581}
1582EXPORT_SYMBOL(i2c_register_driver);
1583
1584static int __process_removed_driver(struct device *dev, void *data)
1585{
1586 if (dev->type == &i2c_adapter_type)
1587 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1588 return 0;
1589}
1590
1591/**
1592 * i2c_del_driver - unregister I2C driver
1593 * @driver: the driver being unregistered
1594 * Context: can sleep
1595 */
1596void i2c_del_driver(struct i2c_driver *driver)
1597{
1598 i2c_for_each_dev(driver, __process_removed_driver);
1599
1600 driver_unregister(&driver->driver);
1601 pr_debug("i2c-core: driver [%s] unregistered\n", driver->driver.name);
1602}
1603EXPORT_SYMBOL(i2c_del_driver);
1604
1605/* ------------------------------------------------------------------------- */
1606
1607/**
1608 * i2c_use_client - increments the reference count of the i2c client structure
1609 * @client: the client being referenced
1610 *
1611 * Each live reference to a client should be refcounted. The driver model does
1612 * that automatically as part of driver binding, so that most drivers don't
1613 * need to do this explicitly: they hold a reference until they're unbound
1614 * from the device.
1615 *
1616 * A pointer to the client with the incremented reference counter is returned.
1617 */
1618struct i2c_client *i2c_use_client(struct i2c_client *client)
1619{
1620 if (client && get_device(&client->dev))
1621 return client;
1622 return NULL;
1623}
1624EXPORT_SYMBOL(i2c_use_client);
1625
1626/**
1627 * i2c_release_client - release a use of the i2c client structure
1628 * @client: the client being no longer referenced
1629 *
1630 * Must be called when a user of a client is finished with it.
1631 */
1632void i2c_release_client(struct i2c_client *client)
1633{
1634 if (client)
1635 put_device(&client->dev);
1636}
1637EXPORT_SYMBOL(i2c_release_client);
1638
1639struct i2c_cmd_arg {
1640 unsigned cmd;
1641 void *arg;
1642};
1643
1644static int i2c_cmd(struct device *dev, void *_arg)
1645{
1646 struct i2c_client *client = i2c_verify_client(dev);
1647 struct i2c_cmd_arg *arg = _arg;
1648 struct i2c_driver *driver;
1649
1650 if (!client || !client->dev.driver)
1651 return 0;
1652
1653 driver = to_i2c_driver(client->dev.driver);
1654 if (driver->command)
1655 driver->command(client, arg->cmd, arg->arg);
1656 return 0;
1657}
1658
1659void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1660{
1661 struct i2c_cmd_arg cmd_arg;
1662
1663 cmd_arg.cmd = cmd;
1664 cmd_arg.arg = arg;
1665 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1666}
1667EXPORT_SYMBOL(i2c_clients_command);
1668
1669static int __init i2c_init(void)
1670{
1671 int retval;
1672
1673 retval = bus_register(&i2c_bus_type);
1674 if (retval)
1675 return retval;
1676#ifdef CONFIG_I2C_COMPAT
1677 i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1678 if (!i2c_adapter_compat_class) {
1679 retval = -ENOMEM;
1680 goto bus_err;
1681 }
1682#endif
1683 retval = i2c_add_driver(&dummy_driver);
1684 if (retval)
1685 goto class_err;
1686 return 0;
1687
1688class_err:
1689#ifdef CONFIG_I2C_COMPAT
1690 class_compat_unregister(i2c_adapter_compat_class);
1691bus_err:
1692#endif
1693 bus_unregister(&i2c_bus_type);
1694 return retval;
1695}
1696
1697static void __exit i2c_exit(void)
1698{
1699 i2c_del_driver(&dummy_driver);
1700#ifdef CONFIG_I2C_COMPAT
1701 class_compat_unregister(i2c_adapter_compat_class);
1702#endif
1703 bus_unregister(&i2c_bus_type);
1704 tracepoint_synchronize_unregister();
1705}
1706
1707/* We must initialize early, because some subsystems register i2c drivers
1708 * in subsys_initcall() code, but are linked (and initialized) before i2c.
1709 */
1710postcore_initcall(i2c_init);
1711module_exit(i2c_exit);
1712
1713/* ----------------------------------------------------
1714 * the functional interface to the i2c busses.
1715 * ----------------------------------------------------
1716 */
1717
1718/**
1719 * __i2c_transfer - unlocked flavor of i2c_transfer
1720 * @adap: Handle to I2C bus
1721 * @msgs: One or more messages to execute before STOP is issued to
1722 * terminate the operation; each message begins with a START.
1723 * @num: Number of messages to be executed.
1724 *
1725 * Returns negative errno, else the number of messages executed.
1726 *
1727 * Adapter lock must be held when calling this function. No debug logging
1728 * takes place. adap->algo->master_xfer existence isn't checked.
1729 */
1730int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1731{
1732 unsigned long orig_jiffies;
1733 int ret, try;
1734
1735 /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
1736 * enabled. This is an efficient way of keeping the for-loop from
1737 * being executed when not needed.
1738 */
1739 if (static_key_false(&i2c_trace_msg)) {
1740 int i;
1741 for (i = 0; i < num; i++)
1742 if (msgs[i].flags & I2C_M_RD)
1743 trace_i2c_read(adap, &msgs[i], i);
1744 else
1745 trace_i2c_write(adap, &msgs[i], i);
1746 }
1747
1748 /* Retry automatically on arbitration loss */
1749 orig_jiffies = jiffies;
1750 for (ret = 0, try = 0; try <= adap->retries; try++) {
1751 ret = adap->algo->master_xfer(adap, msgs, num);
1752 if (ret != -EAGAIN)
1753 break;
1754 if (time_after(jiffies, orig_jiffies + adap->timeout))
1755 break;
1756 }
1757
1758 if (static_key_false(&i2c_trace_msg)) {
1759 int i;
1760 for (i = 0; i < ret; i++)
1761 if (msgs[i].flags & I2C_M_RD)
1762 trace_i2c_reply(adap, &msgs[i], i);
1763 trace_i2c_result(adap, i, ret);
1764 }
1765
1766 return ret;
1767}
1768EXPORT_SYMBOL(__i2c_transfer);
1769
1770/**
1771 * i2c_transfer - execute a single or combined I2C message
1772 * @adap: Handle to I2C bus
1773 * @msgs: One or more messages to execute before STOP is issued to
1774 * terminate the operation; each message begins with a START.
1775 * @num: Number of messages to be executed.
1776 *
1777 * Returns negative errno, else the number of messages executed.
1778 *
1779 * Note that there is no requirement that each message be sent to
1780 * the same slave address, although that is the most common model.
1781 */
1782int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1783{
1784 int ret;
1785
1786 /* REVISIT the fault reporting model here is weak:
1787 *
1788 * - When we get an error after receiving N bytes from a slave,
1789 * there is no way to report "N".
1790 *
1791 * - When we get a NAK after transmitting N bytes to a slave,
1792 * there is no way to report "N" ... or to let the master
1793 * continue executing the rest of this combined message, if
1794 * that's the appropriate response.
1795 *
1796 * - When for example "num" is two and we successfully complete
1797 * the first message but get an error part way through the
1798 * second, it's unclear whether that should be reported as
1799 * one (discarding status on the second message) or errno
1800 * (discarding status on the first one).
1801 */
1802
1803 if (adap->algo->master_xfer) {
1804#ifdef DEBUG
1805 for (ret = 0; ret < num; ret++) {
1806 dev_dbg(&adap->dev, "master_xfer[%d] %c, addr=0x%02x, "
1807 "len=%d%s\n", ret, (msgs[ret].flags & I2C_M_RD)
1808 ? 'R' : 'W', msgs[ret].addr, msgs[ret].len,
1809 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1810 }
1811#endif
1812
1813 if (in_atomic() || irqs_disabled()) {
1814 ret = i2c_trylock_adapter(adap);
1815 if (!ret)
1816 /* I2C activity is ongoing. */
1817 return -EAGAIN;
1818 } else {
1819 i2c_lock_adapter(adap);
1820 }
1821
1822 ret = __i2c_transfer(adap, msgs, num);
1823 i2c_unlock_adapter(adap);
1824
1825 return ret;
1826 } else {
1827 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1828 return -EOPNOTSUPP;
1829 }
1830}
1831EXPORT_SYMBOL(i2c_transfer);
1832
1833/**
1834 * i2c_master_send - issue a single I2C message in master transmit mode
1835 * @client: Handle to slave device
1836 * @buf: Data that will be written to the slave
1837 * @count: How many bytes to write, must be less than 64k since msg.len is u16
1838 *
1839 * Returns negative errno, or else the number of bytes written.
1840 */
1841int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
1842{
1843 int ret;
1844 struct i2c_adapter *adap = client->adapter;
1845 struct i2c_msg msg;
1846
1847 msg.addr = client->addr;
1848 msg.flags = client->flags & I2C_M_TEN;
1849 msg.len = count;
1850 msg.buf = (char *)buf;
1851
1852 ret = i2c_transfer(adap, &msg, 1);
1853
1854 /*
1855 * If everything went ok (i.e. 1 msg transmitted), return #bytes
1856 * transmitted, else error code.
1857 */
1858 return (ret == 1) ? count : ret;
1859}
1860EXPORT_SYMBOL(i2c_master_send);
1861
1862/**
1863 * i2c_master_recv - issue a single I2C message in master receive mode
1864 * @client: Handle to slave device
1865 * @buf: Where to store data read from slave
1866 * @count: How many bytes to read, must be less than 64k since msg.len is u16
1867 *
1868 * Returns negative errno, or else the number of bytes read.
1869 */
1870int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
1871{
1872 struct i2c_adapter *adap = client->adapter;
1873 struct i2c_msg msg;
1874 int ret;
1875
1876 msg.addr = client->addr;
1877 msg.flags = client->flags & I2C_M_TEN;
1878 msg.flags |= I2C_M_RD;
1879 msg.len = count;
1880 msg.buf = buf;
1881
1882 ret = i2c_transfer(adap, &msg, 1);
1883
1884 /*
1885 * If everything went ok (i.e. 1 msg received), return #bytes received,
1886 * else error code.
1887 */
1888 return (ret == 1) ? count : ret;
1889}
1890EXPORT_SYMBOL(i2c_master_recv);
1891
1892/* ----------------------------------------------------
1893 * the i2c address scanning function
1894 * Will not work for 10-bit addresses!
1895 * ----------------------------------------------------
1896 */
1897
1898/*
1899 * Legacy default probe function, mostly relevant for SMBus. The default
1900 * probe method is a quick write, but it is known to corrupt the 24RF08
1901 * EEPROMs due to a state machine bug, and could also irreversibly
1902 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
1903 * we use a short byte read instead. Also, some bus drivers don't implement
1904 * quick write, so we fallback to a byte read in that case too.
1905 * On x86, there is another special case for FSC hardware monitoring chips,
1906 * which want regular byte reads (address 0x73.) Fortunately, these are the
1907 * only known chips using this I2C address on PC hardware.
1908 * Returns 1 if probe succeeded, 0 if not.
1909 */
1910static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
1911{
1912 int err;
1913 union i2c_smbus_data dummy;
1914
1915#ifdef CONFIG_X86
1916 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
1917 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
1918 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
1919 I2C_SMBUS_BYTE_DATA, &dummy);
1920 else
1921#endif
1922 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
1923 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
1924 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
1925 I2C_SMBUS_QUICK, NULL);
1926 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
1927 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
1928 I2C_SMBUS_BYTE, &dummy);
1929 else {
1930 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
1931 addr);
1932 err = -EOPNOTSUPP;
1933 }
1934
1935 return err >= 0;
1936}
1937
1938static int i2c_detect_address(struct i2c_client *temp_client,
1939 struct i2c_driver *driver)
1940{
1941 struct i2c_board_info info;
1942 struct i2c_adapter *adapter = temp_client->adapter;
1943 int addr = temp_client->addr;
1944 int err;
1945
1946 /* Make sure the address is valid */
1947 err = i2c_check_addr_validity(addr);
1948 if (err) {
1949 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
1950 addr);
1951 return err;
1952 }
1953
1954 /* Skip if already in use */
1955 if (i2c_check_addr_busy(adapter, addr))
1956 return 0;
1957
1958 /* Make sure there is something at this address */
1959 if (!i2c_default_probe(adapter, addr))
1960 return 0;
1961
1962 /* Finally call the custom detection function */
1963 memset(&info, 0, sizeof(struct i2c_board_info));
1964 info.addr = addr;
1965 err = driver->detect(temp_client, &info);
1966 if (err) {
1967 /* -ENODEV is returned if the detection fails. We catch it
1968 here as this isn't an error. */
1969 return err == -ENODEV ? 0 : err;
1970 }
1971
1972 /* Consistency check */
1973 if (info.type[0] == '\0') {
1974 dev_err(&adapter->dev, "%s detection function provided "
1975 "no name for 0x%x\n", driver->driver.name,
1976 addr);
1977 } else {
1978 struct i2c_client *client;
1979
1980 /* Detection succeeded, instantiate the device */
1981 if (adapter->class & I2C_CLASS_DEPRECATED)
1982 dev_warn(&adapter->dev,
1983 "This adapter will soon drop class based instantiation of devices. "
1984 "Please make sure client 0x%02x gets instantiated by other means. "
1985 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
1986 info.addr);
1987
1988 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
1989 info.type, info.addr);
1990 client = i2c_new_device(adapter, &info);
1991 if (client)
1992 list_add_tail(&client->detected, &driver->clients);
1993 else
1994 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
1995 info.type, info.addr);
1996 }
1997 return 0;
1998}
1999
2000static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2001{
2002 const unsigned short *address_list;
2003 struct i2c_client *temp_client;
2004 int i, err = 0;
2005 int adap_id = i2c_adapter_id(adapter);
2006
2007 address_list = driver->address_list;
2008 if (!driver->detect || !address_list)
2009 return 0;
2010
2011 /* Stop here if the classes do not match */
2012 if (!(adapter->class & driver->class))
2013 return 0;
2014
2015 /* Set up a temporary client to help detect callback */
2016 temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2017 if (!temp_client)
2018 return -ENOMEM;
2019 temp_client->adapter = adapter;
2020
2021 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2022 dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
2023 "addr 0x%02x\n", adap_id, address_list[i]);
2024 temp_client->addr = address_list[i];
2025 err = i2c_detect_address(temp_client, driver);
2026 if (unlikely(err))
2027 break;
2028 }
2029
2030 kfree(temp_client);
2031 return err;
2032}
2033
2034int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2035{
2036 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2037 I2C_SMBUS_QUICK, NULL) >= 0;
2038}
2039EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2040
2041struct i2c_client *
2042i2c_new_probed_device(struct i2c_adapter *adap,
2043 struct i2c_board_info *info,
2044 unsigned short const *addr_list,
2045 int (*probe)(struct i2c_adapter *, unsigned short addr))
2046{
2047 int i;
2048
2049 if (!probe)
2050 probe = i2c_default_probe;
2051
2052 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2053 /* Check address validity */
2054 if (i2c_check_addr_validity(addr_list[i]) < 0) {
2055 dev_warn(&adap->dev, "Invalid 7-bit address "
2056 "0x%02x\n", addr_list[i]);
2057 continue;
2058 }
2059
2060 /* Check address availability */
2061 if (i2c_check_addr_busy(adap, addr_list[i])) {
2062 dev_dbg(&adap->dev, "Address 0x%02x already in "
2063 "use, not probing\n", addr_list[i]);
2064 continue;
2065 }
2066
2067 /* Test address responsiveness */
2068 if (probe(adap, addr_list[i]))
2069 break;
2070 }
2071
2072 if (addr_list[i] == I2C_CLIENT_END) {
2073 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2074 return NULL;
2075 }
2076
2077 info->addr = addr_list[i];
2078 return i2c_new_device(adap, info);
2079}
2080EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2081
2082struct i2c_adapter *i2c_get_adapter(int nr)
2083{
2084 struct i2c_adapter *adapter;
2085
2086 mutex_lock(&core_lock);
2087 adapter = idr_find(&i2c_adapter_idr, nr);
2088 if (adapter && !try_module_get(adapter->owner))
2089 adapter = NULL;
2090
2091 mutex_unlock(&core_lock);
2092 return adapter;
2093}
2094EXPORT_SYMBOL(i2c_get_adapter);
2095
2096void i2c_put_adapter(struct i2c_adapter *adap)
2097{
2098 if (adap)
2099 module_put(adap->owner);
2100}
2101EXPORT_SYMBOL(i2c_put_adapter);
2102
2103/* The SMBus parts */
2104
2105#define POLY (0x1070U << 3)
2106static u8 crc8(u16 data)
2107{
2108 int i;
2109
2110 for (i = 0; i < 8; i++) {
2111 if (data & 0x8000)
2112 data = data ^ POLY;
2113 data = data << 1;
2114 }
2115 return (u8)(data >> 8);
2116}
2117
2118/* Incremental CRC8 over count bytes in the array pointed to by p */
2119static u8 i2c_smbus_pec(u8 crc, u8 *p, size_t count)
2120{
2121 int i;
2122
2123 for (i = 0; i < count; i++)
2124 crc = crc8((crc ^ p[i]) << 8);
2125 return crc;
2126}
2127
2128/* Assume a 7-bit address, which is reasonable for SMBus */
2129static u8 i2c_smbus_msg_pec(u8 pec, struct i2c_msg *msg)
2130{
2131 /* The address will be sent first */
2132 u8 addr = (msg->addr << 1) | !!(msg->flags & I2C_M_RD);
2133 pec = i2c_smbus_pec(pec, &addr, 1);
2134
2135 /* The data buffer follows */
2136 return i2c_smbus_pec(pec, msg->buf, msg->len);
2137}
2138
2139/* Used for write only transactions */
2140static inline void i2c_smbus_add_pec(struct i2c_msg *msg)
2141{
2142 msg->buf[msg->len] = i2c_smbus_msg_pec(0, msg);
2143 msg->len++;
2144}
2145
2146/* Return <0 on CRC error
2147 If there was a write before this read (most cases) we need to take the
2148 partial CRC from the write part into account.
2149 Note that this function does modify the message (we need to decrease the
2150 message length to hide the CRC byte from the caller). */
2151static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
2152{
2153 u8 rpec = msg->buf[--msg->len];
2154 cpec = i2c_smbus_msg_pec(cpec, msg);
2155
2156 if (rpec != cpec) {
2157 pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
2158 rpec, cpec);
2159 return -EBADMSG;
2160 }
2161 return 0;
2162}
2163
2164/**
2165 * i2c_smbus_read_byte - SMBus "receive byte" protocol
2166 * @client: Handle to slave device
2167 *
2168 * This executes the SMBus "receive byte" protocol, returning negative errno
2169 * else the byte received from the device.
2170 */
2171s32 i2c_smbus_read_byte(const struct i2c_client *client)
2172{
2173 union i2c_smbus_data data;
2174 int status;
2175
2176 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2177 I2C_SMBUS_READ, 0,
2178 I2C_SMBUS_BYTE, &data);
2179 return (status < 0) ? status : data.byte;
2180}
2181EXPORT_SYMBOL(i2c_smbus_read_byte);
2182
2183/**
2184 * i2c_smbus_write_byte - SMBus "send byte" protocol
2185 * @client: Handle to slave device
2186 * @value: Byte to be sent
2187 *
2188 * This executes the SMBus "send byte" protocol, returning negative errno
2189 * else zero on success.
2190 */
2191s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
2192{
2193 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2194 I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
2195}
2196EXPORT_SYMBOL(i2c_smbus_write_byte);
2197
2198/**
2199 * i2c_smbus_read_byte_data - SMBus "read byte" protocol
2200 * @client: Handle to slave device
2201 * @command: Byte interpreted by slave
2202 *
2203 * This executes the SMBus "read byte" protocol, returning negative errno
2204 * else a data byte received from the device.
2205 */
2206s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command)
2207{
2208 union i2c_smbus_data data;
2209 int status;
2210
2211 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2212 I2C_SMBUS_READ, command,
2213 I2C_SMBUS_BYTE_DATA, &data);
2214 return (status < 0) ? status : data.byte;
2215}
2216EXPORT_SYMBOL(i2c_smbus_read_byte_data);
2217
2218/**
2219 * i2c_smbus_write_byte_data - SMBus "write byte" protocol
2220 * @client: Handle to slave device
2221 * @command: Byte interpreted by slave
2222 * @value: Byte being written
2223 *
2224 * This executes the SMBus "write byte" protocol, returning negative errno
2225 * else zero on success.
2226 */
2227s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
2228 u8 value)
2229{
2230 union i2c_smbus_data data;
2231 data.byte = value;
2232 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2233 I2C_SMBUS_WRITE, command,
2234 I2C_SMBUS_BYTE_DATA, &data);
2235}
2236EXPORT_SYMBOL(i2c_smbus_write_byte_data);
2237
2238/**
2239 * i2c_smbus_read_word_data - SMBus "read word" protocol
2240 * @client: Handle to slave device
2241 * @command: Byte interpreted by slave
2242 *
2243 * This executes the SMBus "read word" protocol, returning negative errno
2244 * else a 16-bit unsigned "word" received from the device.
2245 */
2246s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
2247{
2248 union i2c_smbus_data data;
2249 int status;
2250
2251 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2252 I2C_SMBUS_READ, command,
2253 I2C_SMBUS_WORD_DATA, &data);
2254 return (status < 0) ? status : data.word;
2255}
2256EXPORT_SYMBOL(i2c_smbus_read_word_data);
2257
2258/**
2259 * i2c_smbus_write_word_data - SMBus "write word" protocol
2260 * @client: Handle to slave device
2261 * @command: Byte interpreted by slave
2262 * @value: 16-bit "word" being written
2263 *
2264 * This executes the SMBus "write word" protocol, returning negative errno
2265 * else zero on success.
2266 */
2267s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
2268 u16 value)
2269{
2270 union i2c_smbus_data data;
2271 data.word = value;
2272 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2273 I2C_SMBUS_WRITE, command,
2274 I2C_SMBUS_WORD_DATA, &data);
2275}
2276EXPORT_SYMBOL(i2c_smbus_write_word_data);
2277
2278/**
2279 * i2c_smbus_read_block_data - SMBus "block read" protocol
2280 * @client: Handle to slave device
2281 * @command: Byte interpreted by slave
2282 * @values: Byte array into which data will be read; big enough to hold
2283 * the data returned by the slave. SMBus allows at most 32 bytes.
2284 *
2285 * This executes the SMBus "block read" protocol, returning negative errno
2286 * else the number of data bytes in the slave's response.
2287 *
2288 * Note that using this function requires that the client's adapter support
2289 * the I2C_FUNC_SMBUS_READ_BLOCK_DATA functionality. Not all adapter drivers
2290 * support this; its emulation through I2C messaging relies on a specific
2291 * mechanism (I2C_M_RECV_LEN) which may not be implemented.
2292 */
2293s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
2294 u8 *values)
2295{
2296 union i2c_smbus_data data;
2297 int status;
2298
2299 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2300 I2C_SMBUS_READ, command,
2301 I2C_SMBUS_BLOCK_DATA, &data);
2302 if (status)
2303 return status;
2304
2305 memcpy(values, &data.block[1], data.block[0]);
2306 return data.block[0];
2307}
2308EXPORT_SYMBOL(i2c_smbus_read_block_data);
2309
2310/**
2311 * i2c_smbus_write_block_data - SMBus "block write" protocol
2312 * @client: Handle to slave device
2313 * @command: Byte interpreted by slave
2314 * @length: Size of data block; SMBus allows at most 32 bytes
2315 * @values: Byte array which will be written.
2316 *
2317 * This executes the SMBus "block write" protocol, returning negative errno
2318 * else zero on success.
2319 */
2320s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
2321 u8 length, const u8 *values)
2322{
2323 union i2c_smbus_data data;
2324
2325 if (length > I2C_SMBUS_BLOCK_MAX)
2326 length = I2C_SMBUS_BLOCK_MAX;
2327 data.block[0] = length;
2328 memcpy(&data.block[1], values, length);
2329 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2330 I2C_SMBUS_WRITE, command,
2331 I2C_SMBUS_BLOCK_DATA, &data);
2332}
2333EXPORT_SYMBOL(i2c_smbus_write_block_data);
2334
2335/* Returns the number of read bytes */
2336s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
2337 u8 length, u8 *values)
2338{
2339 union i2c_smbus_data data;
2340 int status;
2341
2342 if (length > I2C_SMBUS_BLOCK_MAX)
2343 length = I2C_SMBUS_BLOCK_MAX;
2344 data.block[0] = length;
2345 status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2346 I2C_SMBUS_READ, command,
2347 I2C_SMBUS_I2C_BLOCK_DATA, &data);
2348 if (status < 0)
2349 return status;
2350
2351 memcpy(values, &data.block[1], data.block[0]);
2352 return data.block[0];
2353}
2354EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
2355
2356s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
2357 u8 length, const u8 *values)
2358{
2359 union i2c_smbus_data data;
2360
2361 if (length > I2C_SMBUS_BLOCK_MAX)
2362 length = I2C_SMBUS_BLOCK_MAX;
2363 data.block[0] = length;
2364 memcpy(data.block + 1, values, length);
2365 return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
2366 I2C_SMBUS_WRITE, command,
2367 I2C_SMBUS_I2C_BLOCK_DATA, &data);
2368}
2369EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data);
2370
2371/* Simulate a SMBus command using the i2c protocol
2372 No checking of parameters is done! */
2373static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
2374 unsigned short flags,
2375 char read_write, u8 command, int size,
2376 union i2c_smbus_data *data)
2377{
2378 /* So we need to generate a series of msgs. In the case of writing, we
2379 need to use only one message; when reading, we need two. We initialize
2380 most things with sane defaults, to keep the code below somewhat
2381 simpler. */
2382 unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX+3];
2383 unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX+2];
2384 int num = read_write == I2C_SMBUS_READ ? 2 : 1;
2385 int i;
2386 u8 partial_pec = 0;
2387 int status;
2388 struct i2c_msg msg[2] = {
2389 {
2390 .addr = addr,
2391 .flags = flags,
2392 .len = 1,
2393 .buf = msgbuf0,
2394 }, {
2395 .addr = addr,
2396 .flags = flags | I2C_M_RD,
2397 .len = 0,
2398 .buf = msgbuf1,
2399 },
2400 };
2401
2402 msgbuf0[0] = command;
2403 switch (size) {
2404 case I2C_SMBUS_QUICK:
2405 msg[0].len = 0;
2406 /* Special case: The read/write field is used as data */
2407 msg[0].flags = flags | (read_write == I2C_SMBUS_READ ?
2408 I2C_M_RD : 0);
2409 num = 1;
2410 break;
2411 case I2C_SMBUS_BYTE:
2412 if (read_write == I2C_SMBUS_READ) {
2413 /* Special case: only a read! */
2414 msg[0].flags = I2C_M_RD | flags;
2415 num = 1;
2416 }
2417 break;
2418 case I2C_SMBUS_BYTE_DATA:
2419 if (read_write == I2C_SMBUS_READ)
2420 msg[1].len = 1;
2421 else {
2422 msg[0].len = 2;
2423 msgbuf0[1] = data->byte;
2424 }
2425 break;
2426 case I2C_SMBUS_WORD_DATA:
2427 if (read_write == I2C_SMBUS_READ)
2428 msg[1].len = 2;
2429 else {
2430 msg[0].len = 3;
2431 msgbuf0[1] = data->word & 0xff;
2432 msgbuf0[2] = data->word >> 8;
2433 }
2434 break;
2435 case I2C_SMBUS_PROC_CALL:
2436 num = 2; /* Special case */
2437 read_write = I2C_SMBUS_READ;
2438 msg[0].len = 3;
2439 msg[1].len = 2;
2440 msgbuf0[1] = data->word & 0xff;
2441 msgbuf0[2] = data->word >> 8;
2442 break;
2443 case I2C_SMBUS_BLOCK_DATA:
2444 if (read_write == I2C_SMBUS_READ) {
2445 msg[1].flags |= I2C_M_RECV_LEN;
2446 msg[1].len = 1; /* block length will be added by
2447 the underlying bus driver */
2448 } else {
2449 msg[0].len = data->block[0] + 2;
2450 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
2451 dev_err(&adapter->dev,
2452 "Invalid block write size %d\n",
2453 data->block[0]);
2454 return -EINVAL;
2455 }
2456 for (i = 1; i < msg[0].len; i++)
2457 msgbuf0[i] = data->block[i-1];
2458 }
2459 break;
2460 case I2C_SMBUS_BLOCK_PROC_CALL:
2461 num = 2; /* Another special case */
2462 read_write = I2C_SMBUS_READ;
2463 if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
2464 dev_err(&adapter->dev,
2465 "Invalid block write size %d\n",
2466 data->block[0]);
2467 return -EINVAL;
2468 }
2469 msg[0].len = data->block[0] + 2;
2470 for (i = 1; i < msg[0].len; i++)
2471 msgbuf0[i] = data->block[i-1];
2472 msg[1].flags |= I2C_M_RECV_LEN;
2473 msg[1].len = 1; /* block length will be added by
2474 the underlying bus driver */
2475 break;
2476 case I2C_SMBUS_I2C_BLOCK_DATA:
2477 if (read_write == I2C_SMBUS_READ) {
2478 msg[1].len = data->block[0];
2479 } else {
2480 msg[0].len = data->block[0] + 1;
2481 if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
2482 dev_err(&adapter->dev,
2483 "Invalid block write size %d\n",
2484 data->block[0]);
2485 return -EINVAL;
2486 }
2487 for (i = 1; i <= data->block[0]; i++)
2488 msgbuf0[i] = data->block[i];
2489 }
2490 break;
2491 default:
2492 dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
2493 return -EOPNOTSUPP;
2494 }
2495
2496 i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
2497 && size != I2C_SMBUS_I2C_BLOCK_DATA);
2498 if (i) {
2499 /* Compute PEC if first message is a write */
2500 if (!(msg[0].flags & I2C_M_RD)) {
2501 if (num == 1) /* Write only */
2502 i2c_smbus_add_pec(&msg[0]);
2503 else /* Write followed by read */
2504 partial_pec = i2c_smbus_msg_pec(0, &msg[0]);
2505 }
2506 /* Ask for PEC if last message is a read */
2507 if (msg[num-1].flags & I2C_M_RD)
2508 msg[num-1].len++;
2509 }
2510
2511 status = i2c_transfer(adapter, msg, num);
2512 if (status < 0)
2513 return status;
2514
2515 /* Check PEC if last message is a read */
2516 if (i && (msg[num-1].flags & I2C_M_RD)) {
2517 status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
2518 if (status < 0)
2519 return status;
2520 }
2521
2522 if (read_write == I2C_SMBUS_READ)
2523 switch (size) {
2524 case I2C_SMBUS_BYTE:
2525 data->byte = msgbuf0[0];
2526 break;
2527 case I2C_SMBUS_BYTE_DATA:
2528 data->byte = msgbuf1[0];
2529 break;
2530 case I2C_SMBUS_WORD_DATA:
2531 case I2C_SMBUS_PROC_CALL:
2532 data->word = msgbuf1[0] | (msgbuf1[1] << 8);
2533 break;
2534 case I2C_SMBUS_I2C_BLOCK_DATA:
2535 for (i = 0; i < data->block[0]; i++)
2536 data->block[i+1] = msgbuf1[i];
2537 break;
2538 case I2C_SMBUS_BLOCK_DATA:
2539 case I2C_SMBUS_BLOCK_PROC_CALL:
2540 for (i = 0; i < msgbuf1[0] + 1; i++)
2541 data->block[i] = msgbuf1[i];
2542 break;
2543 }
2544 return 0;
2545}
2546
2547/**
2548 * i2c_smbus_xfer - execute SMBus protocol operations
2549 * @adapter: Handle to I2C bus
2550 * @addr: Address of SMBus slave on that bus
2551 * @flags: I2C_CLIENT_* flags (usually zero or I2C_CLIENT_PEC)
2552 * @read_write: I2C_SMBUS_READ or I2C_SMBUS_WRITE
2553 * @command: Byte interpreted by slave, for protocols which use such bytes
2554 * @protocol: SMBus protocol operation to execute, such as I2C_SMBUS_PROC_CALL
2555 * @data: Data to be read or written
2556 *
2557 * This executes an SMBus protocol operation, and returns a negative
2558 * errno code else zero on success.
2559 */
2560s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags,
2561 char read_write, u8 command, int protocol,
2562 union i2c_smbus_data *data)
2563{
2564 unsigned long orig_jiffies;
2565 int try;
2566 s32 res;
2567
2568 /* If enabled, the following two tracepoints are conditional on
2569 * read_write and protocol.
2570 */
2571 trace_smbus_write(adapter, addr, flags, read_write,
2572 command, protocol, data);
2573 trace_smbus_read(adapter, addr, flags, read_write,
2574 command, protocol);
2575
2576 flags &= I2C_M_TEN | I2C_CLIENT_PEC | I2C_CLIENT_SCCB;
2577
2578 if (adapter->algo->smbus_xfer) {
2579 i2c_lock_adapter(adapter);
2580
2581 /* Retry automatically on arbitration loss */
2582 orig_jiffies = jiffies;
2583 for (res = 0, try = 0; try <= adapter->retries; try++) {
2584 res = adapter->algo->smbus_xfer(adapter, addr, flags,
2585 read_write, command,
2586 protocol, data);
2587 if (res != -EAGAIN)
2588 break;
2589 if (time_after(jiffies,
2590 orig_jiffies + adapter->timeout))
2591 break;
2592 }
2593 i2c_unlock_adapter(adapter);
2594
2595 if (res != -EOPNOTSUPP || !adapter->algo->master_xfer)
2596 goto trace;
2597 /*
2598 * Fall back to i2c_smbus_xfer_emulated if the adapter doesn't
2599 * implement native support for the SMBus operation.
2600 */
2601 }
2602
2603 res = i2c_smbus_xfer_emulated(adapter, addr, flags, read_write,
2604 command, protocol, data);
2605
2606trace:
2607 /* If enabled, the reply tracepoint is conditional on read_write. */
2608 trace_smbus_reply(adapter, addr, flags, read_write,
2609 command, protocol, data);
2610 trace_smbus_result(adapter, addr, flags, read_write,
2611 command, protocol, res);
2612
2613 return res;
2614}
2615EXPORT_SYMBOL(i2c_smbus_xfer);
2616
2617MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2618MODULE_DESCRIPTION("I2C-Bus main module");
2619MODULE_LICENSE("GPL");